Patent Publication Number: US-10321743-B2

Title: Square princess cut gemstone

Description:
RELATED APPLICATION 
     This utility application claims priority from U.S. Patent Application No. 62/022,680 entitled, “Square Princess Cut Diamond” filed on Jul. 10, 2014, the entirety of which is hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     A square princess cut diamond has a square girdle, a crown above the girdle, and a pavilion below the girdle. The crown of a square princess cut diamond has conventionally comprised a central table facet and at least twenty additional facets. Square cut diamonds have traditionally been appraised by intensity (color strength), brightness (light return), fire (color flashes), and scintillation (sparkles). 
     SUMMARY 
     A square princess cut gemstone is provided wherein, in one example, the crown includes a square central table facet and twelve additional facets. In one example of the present invention, the crown includes a table facet having a square shape with four sides; four upper girdle facets; four table-surrounding facets; and four bezel facets which at least partially straddles regions of at least one of the corner junctions of the upper girdle facets and regions of the corner junctions of the table-surrounding facets. The gemstone, for example a diamond, is able to present excellent ratings of intensity, brightness, fire, and scintillation. This presentation is possible even when the starting stone has a poor color grade and/or when cut imperfections cause symmetry concessions. 
    
    
     
       DRAWINGS 
       The various embodiments of the present invention can be understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Also, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIGS. 1A-1D  show side views of a square princess cut diamond  100  as it is sequentially rotated 90° about a vertical axis, in accordance with an example of the present invention; 
         FIGS. 2A-2D ,  FIGS. 3A-3F , and  FIGS. 4A-4D  show details of the girdle  200 , the crown  300 , and the pavilion  400 , respectively, as the diamond  100  is sequentially rotated 90° about a vertical axis, in accordance to an example of the present invention; 
         FIG. 5  shows the diamond  100  mounted on jewelry pieces  500 . in accordance to an example of the present invention; 
         FIG. 6  shows dimensions and angles of an example embodiment  600  of a diamond, and the measured intensity, brightness, fire, and scintillation therefor, in accordance to an example of the present invention; and 
         FIG. 7  shows a gemstone with chevrons  700  in the pavilion, in accordance to an example of the present invention. 
     
    
    
     DESCRIPTION 
     Various examples of a square cut princess gemstone are disclosed herein. In one example a square cut princess gemstone has a crown that includes a square central table facet and at least twelve (12) additional crown facets. That is, the crown has at least thirteen (13) facets including the central table facet. In another example, a square princess gemstone has a crown that includes a square central table and substantially twelve (12) additional crown facets, namely, four table-surrounding facets, four bezel facets, and four upper-girdle facets. The gemstone also has a pavilion which has a plurality of facets. The number of pavilion facets is at least 16 facets and can typically range from 16 to 33, and so the total number of facets of the gemstone is at least about 33 facets and can range from about 33 to about 50 facets. 
     In another example, the examples of the square cut princess gemstones described above, has a crown that has a square central table facet and twelve additional crown facets has length-width ratio of about 1.0 to about 1.1, or a width-length ratio of about 1.0 to about 1.1. The overall depth ranges from about 80% to about 85%, in another example, about 80% to about 100%, and in another example from about 80% to about 105%. The table size ranges from about 48% to about 54%, and in another example from about 48% to 52%. The princess cut gemstone has a girdle thickness that ranges from greater than about 0% to about 21%, in another example about 0.5% to about 21%, in another example from greater than about 0% to about 7%, and in another example about 6% to about 18%. The crown height ranges from about 15% to about 24%, and in another example, from about 15% to about 18%. The pavilion depth ranges from about 58% to about 65%, and in another example from about from about 60% to about 63%. The gemstone  100  has a crown angle that ranges from about 43° to about 470 and a pavilion angle that ranges from about 39° to 45°, and in another example from about 39° to about 43°. Angle-to-angle tolerances, i.e. between adjacent angles, can be greater than about 2%, greater than about 3%, greater than 4%, in another example up to about 5%, and in other example greater than about 4% and up to about 5%. It has been found that the angle-to-angle tolerances of the example gemstones disclosed herein are greater while maintaining excellent brightness, fire and scintillation. 
       FIGS. 1A through 1D  illustrate square princess cut gemstone  100 , for example a diamond or one of a variety of natural or synthetic gem, Gemstone  100  includes a girdle  200 , a crown  300 , and a pavilion  300 . In the illustrated and industry-accepted orientation, the crown  300  is positioned above the girdle  200  and the pavilion  400  is positioned below the girdle  200 . A square table facet  310  forms a flat top of the crown  300  and a tip  410  forms the bottommost aspect of the pavilion  400 . 
     The diamond  100  has a length dimension L 100  and a width dimension W 100 . The length dimension L 100  is the horizontal distance between one parallel pair of facets of the girdle  200  (i.e., facet  211  and facet  213 ). The width dimension W 100  is the horizontal distance between the girdle&#39;s other parallel pair of facets (i.e., facet  212  and facet  214 ). The diamond  100  can be designated a horizontal dimension H 100  which is the average of its width W 100  and its length L 100 . With a perfectly square cut diamond, the length L 100  would be exactly equal to the width W 100  and the horizontal dimension H 100 . 
     The square table facet  310  has a length dimension L 310  which runs parallel to the diamond&#39;s length dimension L 100  and a width dimension W 310  which runs parallel to the diamond&#39;s width dimension W 100 . The table facet  310  can be designated a horizontal dimension H 310  which is the average of its width W 310  and its length L 310 . Again, with a perfectly square cut diamond, the table length L 310  would be exactly equal to the table width W 310  and the table horizontal dimension H 310 . 
     The diamond  100  also has a vertical dimension V 100  which represents its reach from the table facet  310  to the pavilion tip  410 . The girdle  200  has a vertical dimension V 200  measured between its top edges  231 ,  232 ,  233 ,  234  and its bottom edges  241 ,  242 ,  243 ,  244 . The crown  300  has a vertical dimension V 300  measured from the girdle&#39;s top edges  231 ,  232 ,  233 ,  234  to the table facet  310 . The pavilion  400  has a vertical dimension V 400  measured from the girdle&#39;s bottom edges  241 - 244  to the tip  410 . 
     With reference to  FIG. 1 , an example of gemstone  100  which has length-width ratio (W 100 /L 100  or L 100 /W 100 ) of 1.0 to 1.1, and an overall depth (% V 100 /H 100 ) that ranges from about 80% to about 105%, in another example about 80% to about 100%, and in yet another example about 80% to 85%. The table size (% H 310 /H 100 ) can vary and ranges from about 48% to about 54%, and in another example from about 48% to about 52%. Girdle thickness (% V 200 /H 100 ) can range from greater than about 0% to about 21%, in another example about from 0.5% to about 21%, in another example from greater than about 0% to about 7%, and in another example about 6% to about 18%. The crown height (% V 300 /H 100 ) can range from about 15% to about 24%, and in another example from about 15% to about 18%. The pavilion depth (% V 400 /H 100 ) can range from about 58% to about 65%, and in another example from about 60% to about 63%. 
       FIGS. 2A through 2D  illustrate girdle  200  which can be viewed as occupying a rectangular cuboid region of gemstone  100  between the crown  300  and the pavilion  400 . This rectangular cuboid region forms the four facets  211 ,  212 ,  213 ,  214  which intersect right corner edges. The facets  211 ,  212 ,  213 ,  214  preferably have essentially identical rectangular shapes oriented in vertical planes. As was indicated above, the length L 100  of the diamond  100  is the distance between facet  211  and facet  213 , and the width W 100  of the diamond  100  is the distance between facet  212  and facet  214 . 
     The facets&#39; upper edges  231 ,  232 ,  233 ,  234  form an upper square perimeter and the facets&#39; lower edges  241 - 244  form a lower square perimeter. When the girdle  200  is viewed from the top (with the crown  300  theoretically removed), the girdle&#39;s upper edges  231 ,  232 ,  233 ,  234  define a horizontal square area  230 . When the girdle  200  is viewed from the bottom (with the pavilion  400  theoretically removed), the girdle&#39;s lower edges  241 - 244  define a horizontal square area  240 . 
     The square area  230  and the horizontal square area  240  are parallel (i.e., both oriented in a horizontal plane) and they are vertically aligned. As was indicated above, the girdle&#39;s vertical dimension V 200  is the vertical distance between the square area  230  and the square area  240 . If the diamond  100  is perfectly square, this distance will be the same irrespective of the corresponding coordinates. 
     As was indicated above, the gemstone  100  can have a girdle thickness (% V 200 /H 100 ) that ranges from about 0% to about 7%, in another example from about 0.5% to about 21%, and in another example from about 6% to about 18%. However, one advantage of the present princess cut is that it can adopt thicker girdles than traditional square princess cuts without a significant compromise in intensity, brightness, fire, and scintillation. Such a thicker girdle translates into a greater carat weight, an easier stone-cutting process, and increased chip or break resistance. With specific reference to chip or break resistance, it may be noted that square cut stones are particularly vulnerable to such damage due to the perpendicular nature of the girdle facets  211 ,  212 ,  213 ,  214 . The larger girdle thickness (% V 200 /H 100 ) provides larger surface area for gem cutting decoration to inscribe, for example, serial numbers, pattern designs, and personalized scripture. A thicker girdle also provides for new stone setting techniques and alternative methods for securing the gemstone in a setting, for example. 
       FIGS. 3A through 3D  illustrate crown  300  which has a generally truncated-top pyramid shape with its lower base formed by the girdle&#39;s upper face  230 . Thus the crown  300  has a square base defined by the girdle&#39;s upper edges  231 ,  232 ,  233 ,  234 . The table facet  310  forms the horizontal truncated-top of the crown&#39;s pyramid shape and the four sides of its square shape run parallel to the upper girdle margins  231 ,  232 ,  233 ,  234 . 
     The crown  300  has four upper girdle facets  321 - 324 , four table-surrounding facets  331 - 334 , and four bezel facets  345 - 348 . Thus, the gemstone  100  includes table facet  310  and these twelve additional facets. In one example, gemstone  100  has a maximum of thirteen crown facets including table facet  310 , as shown in  FIG. 3 . In this example, the thirteen crown facets have been found to be capable of conveying high intensity, excellent brightness, excellent fire, and excellent scintillation. This contradicts traditional wisdom that a greater number of crown facets is better when it comes to these performance properties. 
     The upper girdle facets  321 - 324  each have a bezel-modified trapezoidal shape, for example each having four or six sides, and each upper girdle facet  321 - 324  is preferably approximately equal in geometry, that is, approximately equal in shape and size, although variances in size and shape are possible while maintain excellent results. The lower and longer margins  351 - 354  of the upper girdle facets  321 - 324  coincide with the girdle&#39;s upper edges  231 ,  232 ,  233 ,  234 . The upper and shorter margins  361 - 364  of the upper girdle facets  321 - 324  are positioned parallel to the longer margins  351 - 354 , but upward and inward therefrom. 
     The side margins  371 - 374  of each upper girdle facet  321 - 324  slant inwardly to extend between the facet&#39;s lower margins  351 - 354  and upper margins  361 - 364 . The contour of these side margins  371 - 374  will deviate (for example, compared to the straight side margins found in a non-modified trapezoidal shape) to trace the four sides of bezel facets  345 - 348 . The bezels, for example, can have a general parallelogram shape. In another example the bezel is shaped like a kite as shown. The slanted side margins  371 - 374  of the upper girdle facets  321 - 324  merge along a portion of the upper girdle facets, and also merge with bezel facets  345 - 348  along a portion of the upper girdle facets. 
     The upper girdle facets  321 - 324  slant upward from a horizontal plane (e.g., the square area  230  defined by the girdle&#39;s upper edges  231 ,  232 ,  233 ,  234 ) at angles A 321 -A 324 . The average of these upper-girdle-facet angles is considered the crown angle of the diamond  100 . As was indicated above, the gemstone  100  has a crown angle that ranges from about 35° to about 50°, and in another example, from about 43° to 47° depending upon the collective features of the princess cut gemstone. 
     The table-surrounding facets  331 - 334  also have bezel-modified trapezoidal shapes, for example each having four or six sides. The table-surrounding facets  331 - 334  are preferably approximately equal in geometry, for example, substantially equal in size and shape. The lower and longer margins of the table-surrounding facets  331 - 334  coincide with upper margins  361 - 364  of the upper girdle facets  321 - 324 . The upper and shorter margins  391 - 394  of the facets  331 - 334  are positioned parallel to their longer margins  361 - 364 , but upward and inward therefrom. They merge with the outer perimeter sides of the table facet  310 . The bezel-tracing slanted side margins  381 - 384  of the facets  331 - 334  merge with each other and/or the bezel facets  345 - 348 . 
     The table-surrounding facets  331 - 334  slant upward from a horizontal plane at angles A 331 -A 334 . The table-surrounding-facet angles A 331 -A 334  are less than the upper-girdle-facet angles A 321 -A 324  and thus they are less than the diamond&#39;s crown angle. The table-surrounding-facet angles A 331 -A 334  range from about 20° to about 30°, and in another example from about 22° to about 27°. 
     In one example the bezel facets ( 345 ,  346 ,  347 ,  348 ) each have four sides and have a general parallelogram shape. In another example The bezel facets  345 ,  346 ,  347 ,  348  each have four sides and are a kite shape with a bridal portion  345   a ,  346   a ,  347   a ,  348   a  (the larger triangle) and a knot portion  345   b ,  346   b ,  347   b ,  348   b  (the smaller triangle). The bridal portions straddle regions of the corners of adjacent pairs of upper girdle facets  321 - 324  so as to modify the otherwise trapezoidal shape of these facets. The knot portions straddle regions of the corners of adjacent pairs of table-surrounding facets  341 ,  342 ,  343 ,  344  so as to modify their otherwise trapezoidal shape. 
     In the illustrated gemstone  100  of  FIGS. 3A through 3D , the bezel facets  345 ,  346 ,  347 ,  348  are dimensioned so as to straddle top regions of the upper girdle facets  321 - 324  and to straddle bottom regions of the table-surrounding facets  341 ,  342 ,  343 ,  344 . Thus, facets  345 ,  346 ,  347 ,  348  need not extend from the girdle  200  to the table  310  and, for example, bezel facets  345 ,  346 ,  347 ,  348  extend along a portion of each of the girdle facets and along a portion of the table-surrounding facets. That being said, the gemstone  100  in additional examples, includes bezel facets which completely straddle the corners of adjacent upper girdle facets  321 - 324 , as shown in  FIG. 3E , or which completely straddle the corners of adjacent table-surrounding facets  331 - 334 , as shown in  FIG. 3F . In such embodiments the bezel facet can straddle only the corner junctions of the upper girdle facets ( 321 - 324 ) such that the girdle facets ( 321 - 324 ) each have six sides, and the table-surrounding facets ( 331 - 334 ) each have four sides. In another example, the four bezel facets ( 345 - 349 ) straddle regions of the corner junctions of the table-surrounding facets ( 331 - 334 ) such that the table-surrounding facets ( 331 - 334 ) each have six sides, and the upper girdle facets ( 321 - 324 ) each have four sides 
     The bezel facets  345 ,  346 ,  347 ,  348  slant upward from a horizontal plane at facet angles A 345 -A 348 . The bezel-facet angles A 345 -A 348  are less than the upper-girdle-facet angles A 321 -A 24  (and thus the diamond&#39;s crown angle) and greater than the table-surrounding-facet angles A 331 -A 334 . 
     In a perfect cut, the angles A 321 -A 324  are equal, the angles A 331 -A 334  are equal, and the angles A 345 -A 348  are exactly equal. Typically, diamond cuts wherein angle-to-angle tolerances are held to less than 0.5° are considered excellently symmetric. The gemstone  100 , according to various examples, has the advantage of being able to tolerate a larger angle differential among its related or adjacent facets without a sacrifice in overall diamond quality. For example, the upper-girdle-facet angles A 321 -A 324  can vary by more than 1°, the table-surrounding-facet angles A 331 -A 334  can vary by more than 3°, and/or the bezel-facet angles A 345 -A 348  can vary by more than 5°, and in another example, all angles can vary from about 4% to about 5%. 
       FIGS. 4A through 4D  illustrate various features of the gemstone pavilion according to examples of the present invention. The pavilion  400  has a generally inverted pyramid shape with its upper base formed by the girdle&#39;s lower face  240  and its peak formed by the tip  410 . Thus the pavilion  400  has a square base defined by the girdle&#39;s lower edges  241 - 244 . The tip  410  is vertically parallel to this square base and is horizontally centrally located relative thereto. 
     In the illustrated gemstone  100 , the tip  410  is a culet forming a flattened peak in the pavilion&#39;s pyramid shape. The square culet is oriented in a horizontal plane and has sides offset 45° from the lower girdle edges  241 - 244 . However, the tip  410  could instead be a pointed with an apex tangential to a horizontal plane. Such an apex would be considered vertically parallel to the girdle&#39;s lower face  240 . 
     The pavilion  400  can comprise four star facets  425 - 428 , four star-surrounding facet pairs  431 ( a ) and  431 ( b ),  432 ( a ) and  432  ( b ),  433 ( a ) and  433  ( b ), and  434 ( a ) and  431 ( b ), and four lower girdle facets  441 - 444 . 
     The star facets  425 - 428  each have a slender isosceles triangular shape and they collectively occupy a relatively small area of the pavilion surface. The top peaks of the pavilion star facets  425 - 428  are aligned with, and preferably coincide with the corners among the girdle&#39;s lower edges  241 - 244 . The lower bases of the pavilion star facets  425 - 428  coincide with tip  410 . 
     The pavilion&#39;s star facets  425 - 428  each slant downward from a horizontal plane (e.g., the lower square area  240  defined by the girdle&#39;s lower edges  241 - 244 ) at facet angles A 425 -A 428 . The average of these star-facet angles A 425 -A 428  is the pavilion angle. As was indicated above, the diamond  100  has a pavilion angle that ranges from about 39° to about 45°, and in another example from about 39° to about 43°. 
     In the example shown in  FIGS. 4A through 4D , the four facet pairs  431 ( a ) and  431 ( b ),  432 ( a ) and  432  ( b ),  433 ( a ) and  433  ( b ), and  4 ( a ) and  431 ( b ) (thus eight facets in all) surround the star facets  425 - 428 . The facets  431 ( a ) and  431 ( b ), are situated between star facet  428  and star facet  425 , the facets  432 ( a ) and  432  ( b ) are situated between star facet  425  and star facet  426 , the facets  433 ( a ) and  433  ( b ) are situated between star facet  426  and star facet  427 , and the facets  434 ( a ) and  431 ( b ) are situated between star facet  427  and star facet  428 . 
     The star-surrounding facets  431 - 434  each have a triangular shape with a long side (L), a short side (S), and a connecting side (C) therebetween. The long side of each facet coincides with the side of the closest star facet. The short sides of the paired facets merge with each other. 
     The four lower girdle facets  441 - 444  each have a wide isosceles triangle shape. The longer base of each facet  441 - 444  coincides with the girdle&#39;s lower edges  241 ,  242 ,  243 ,  244 . The equal sides of each facet  441 - 444  coincide with the connecting sides of neighboring facet pairs  431 - 434  whereby their peaks meet at the shared boundaries therebetween. 
     The lower girdle facets  441 - 444  extend downward from a horizontal plane (e.g., the square area  240  defined by the girdle&#39;s lower edges  241 - 244 ) at angles A 441 -A 444 . The lower-girdle-facet angles A 441 -A 444  are greater than the star-facet angles A 425 -A 428  and thus greater than the pavilion angle. The lower-girdle-facet angles are range from about 50° to about 60°, in another example from about 55° and 62°. 
     In a perfect cut, the star-facet angles A 425 -A 428  are equal and the lower-girdle-facet angles A 441 -A 444  are equal. Typically a tolerance of 1.2° between related pavilion angles is considered acceptable and will not unduly upset symmetry and thus diamond grading. With the gemstone  100 , larger tolerances can be enjoyed without a decline of intensity, brightness, fire, and/or scintillation. The tolerance for the star-facet angles A 425 -A 428  and/or the tolerance for the lower-girdle-facet angles A 441 -A 444  can be, for example, greater than 2°, in another example the tolerance can range from about 0.5° to about 5°. 
       FIG. 5  illustrates different examples of jewelry  500  that includes one or more gemstone  100 . The square princess cut diamond  100  can be incorporated into jewelry  500  via mounting hardware  510 . The mounting hardware  510  secures one or more gemstones  100  and can be adapted to make finished jewelry, including but not limited to, a ring, an earring, a bracelet, a necklace and combinations thereof. One or more gemstones  100  included in jewelry  500  can include one or more type of natural or synthetic gemstone, for example a diamond, a ruby and an emerald, etc. 
     A sample embodiment  600  of the diamond  100  was tested for intensity, brightness, fire, and scintillation the details of which are described in the Examples below. Example diamond  100  was a princess cut, in accordance with an example of the present invention, and that has a crown with 13 crown facets (including the table facet) and 18 pavilion facets, including extra facets  632  and  634 , for a total of 35 gemstone facets, including four girdle facets, with a point tip  636  having an apex tangential to a horizontal plane. When compared to traditional classifications for square princess cuts, the diamond  600  has a length-width ratio (1.03) which satisfies premium standards (e.g., 0.95-1.05). By current industry standards, diamond  600 &#39;s overall depth (83.3%) is considered average as opposed to premium (e.g., 64% to 75%) or fine (e.g., 58% to 80%). The table size (50.7%) of the diamond  600  is classified as below average instead of average (e.g., 55% to 85%) or above average. Its girdle thickness (5.2%) falls within premium setpoints (e.g., 1.0% to 5.5%). The diamond&#39;s crown height (16.7%) is considered to be within the fine spectrum (e.g., 6% to 18%). 
     The crown  300  angles A 321 -A 324  varying from 44.7° to 46.5° (e.g., greater than 0.5° differential), angles A 331 -A 334  varying from 22.8° to 26.5° (e.g., greater than 3.00 differential), and bezel facets  245 - 248  varying from 28.2° to 29.1° (e.g., greater than 0.5° differential). The pavilion angles A 425 -A 428  vary from 40.0° to 41.2° (e.g., greater than 10 differential) and the pavilion angles A 441 -A 444  vary from 57.20 to 60.9° (e.g., more than a 2° differential). 
     The pavilion  400  of the diamond  600  has an extra star-surrounding facet  632  and an extra star-surrounding facet  634 . Extra diamond facets can be added to the pavilion to remove inclusions and internal flaws found in the crystalline structure of the stone being cut. 
     The symmetry of the diamond  600  is considered poor due its angle variance and extra facets  632  and  634 . Such non-symmetry is usually blamed for inferior scintillation and other desirable diamond properties. But despite this poor symmetry, the diamond  600  still had a high intensity level (71.7% to 77.9%). Measurement results show it had excellent brightness, excellent fire, and excellent scintillation, thereby registering triple-excellent ratings. These values are akin to those achieved by a conventional square princess cut diamond with many more crown facets and which much superior symmetry. Gemstones of the present invention achieve even improved brightness, fire and scintillation with greater balance and symmetry. 
     As was indicated above, the pavilion  400  ( FIGS. 4A-4D ) can comprise four star facets  425 - 428 , four star-surrounding facet pairs  431 - 434 , and four lower girdle facets  441 - 444 . This pavilion facet arrangement will work well in many instances. However,  FIG. 7  illustrates the incorporation of a chevron array  700  into the pavilion  400 , according to another example of the present invention. The incorporation of chevrons may be desirable with some gemstones, for example some diamonds. Specifically, for example, chevrons  741 - 744  can be added to, or used instead of the star-surrounding facet pairs described with respect to  FIGS. 4A-4D . With the illustrated chevron array  700 , three chevrons are situated between each adjacent pair of star facets  425 - 428 . Depending upon diamond characteristics, the chevron count can be adjusted to achieve optimum ratings. The example gemstone  100  of  FIG. 7  has 32 facets plus culet  410  for a total of 33 pavilion facets. Therefore, the total number of gemstone facets is 50, including 13 crown facets and four girdle facets. 
     In order to more fully and clearly describe examples of the present invention, the following examples are given. The examples are intended to illustrate examples of the invention and should not be construed as limiting the invention disclosed and claimed herein in any manner. 
     In accordance with another aspect of the present invention any of the gemstones described above has a crown that has at least 13 facet, in another example, a maximum of 13 facets including the central table facet and substantially twelve (12) additional crown facets, including, four table-surrounding facets, four bezel facets, and four upper-girdle facets. The gemstone also has a pavilion which has at least 16 facets and can typically range from 16 to 33, and so the total number of facets of the gemstone is at least about 33 facets, and in another example the gemstone can have from about 33 to about 50 facets. In another example, the gemstone has a maximum of 34 facets, in another example a maximum of 41 facets, in another example a maximum of 42 facets, in another example a maximum of 49 facets, and in another example a maximum of 50 facets. 
     EXAMPLES 
     Example 1 
     A sample embodiment of diamond  600  ( FIG. 6 ) was tested for intensity, brightness, fire, and scintillation. This testing was performed on a Scanox Proportion HD high resolution proportion system which is commercially available from OGI Systems Ltd. This system was designed for use in situations (e.g., labs) requiring maximum accuracy during diamond scanning. 
     The properties of diamond  600 , including cuts, are listed below in Table 1. The results for intensity, brightness, fire, and scintillation is listed in Table 2. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 Angle 
                   
               
               
                   
                 Property 
                 Measurement 
                 Reference 
                 Angle 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Weight 
                 2.94 
                 Ct. 
                 A321 
                 46.5° 
               
            
           
           
               
               
               
               
               
            
               
                   
                 L/W 
                 1.03 
                 A322 
                 46.1° 
               
               
                   
                 Overall Depth 
                 83.3% 
                 A323 
                 44.7 
               
               
                   
                 Table Size 
                 50.7% 
                 A324 
                 46.4 
               
               
                   
                 Girdle Thickness 
                  5.2% 
                 A331 
                 26.2° 
               
               
                   
                 Crown Height 
                 16.7% 
                 A332 
                 26.5° 
               
               
                   
                 Pavilion Depth 
                 61.4% 
                 A333 
                 22.8° 
               
               
                   
                 Crown Angle 
                 45.9% 
                 A334 
                 24.9° 
               
               
                   
                 Pavilion Angle 
                 40.6% 
                 A335 
                 29.1° 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 L100 
                 7.58 
                 mm 
                 A346 
                 28.3° 
               
               
                   
                 W100 
                 7.39 
                 mm 
                 A347 
                 28.2° 
               
               
                   
                 H100 
                 7.49 
                 mm 
                 A348 
                 28.9° 
               
               
                   
                 H310 
                 3.80 
                 mm 
                 A425 
                 41.2° 
               
               
                   
                 V200 
                 0.4 
                 mm 
                 A426 
                 40.0° 
               
               
                   
                 V300 
                 1.3 
                 mm 
                 A427 
                 40.2° 
               
               
                   
                 V400 
                 4.6 
                 mm 
                 A428 
                 41.0° 
               
            
           
           
               
               
               
               
               
            
               
                   
                 — 
                 — 
                 A441 
                 60.9° 
               
               
                   
                 — 
                 — 
                 A442 
                 57.2° 
               
               
                   
                 — 
                 — 
                 A443 
                 59.4° 
               
               
                   
                 — 
                 — 
                 A444 
                 60.6° 
               
               
                   
                   
               
            
           
         
       
     
     Examples 2 Through 5 
     Square princess cut diamond gemstones having the properties listed in Table 2 were (tested for intensity, brightness, fire, and scintillation. All four crowns are of the type shown in  FIG. 6 , having a square table, four (4) six-sided upper girdle facets, four (4) six-sided table-surrounding facets, and four bezel facts, each of which straddle a portion of the upper-girdle facets and a portion of the table-surrounding facets. 
     All testing was performed on the equipment described above in Example 1. The results showed that these gemstones performed at the top portion of the excellent scale of the Scanox Proportion HD high resolution proportion system. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Example 1 
                   
                   
                   
               
               
                 Properties 
                 (FIG. 6) 
                 Example 2 
                 Example 3 
                 Example 4 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Weight: 
                 2.94 
                 1.99 
                 Ct. 
                 1.81 
                 Ct. 
                 1.98 
                 Ct 
               
            
           
           
               
               
               
               
               
            
               
                 L/W 
                 1.03 
                 1.00 
                 1.0 
                 1.02 
               
               
                 Crown Angle 
                 45.9° 
                 45.8° 
                 45.1° 
                 47.5° 
               
            
           
           
               
               
               
               
               
            
               
                 Crown Height 
                 16.7% 
                 16.9 
                 19.0% 
                 18.5% 
               
            
           
           
               
               
               
               
               
            
               
                 Crown Facets 
                 13 
                 13 
                 13 
                 13 
               
               
                 Pavilion Angle 
                 40.6° 
                 41.1° 
                 40.6° 
                 41.7° 
               
            
           
           
               
               
               
               
               
            
               
                 Pavilion Depth 
                 61.4% 
                 61.4% 
                 61.2% 
                 61.7% 
               
            
           
           
               
               
               
               
               
            
               
                 Pavilion Facets 
                 21 
                 19 
                 21 
                 21 
               
            
           
           
               
               
               
               
               
            
               
                 Table Size 
                 50.7 
                 53.3 
                 48.8% 
                 49.5% 
               
            
           
           
               
               
               
               
               
            
               
                 Girdle Thickness % 
                 5.2% 
                  3.4% 
                  8.9% 
                 15.1% 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Girdle Thickness mm 
                 5.55 mm 
                 5.42 
                 mm 
                 5.65 
                 mm 
                 5.71 
                 mm 
               
            
           
           
               
               
               
               
               
            
               
                 Total Depth 
                 83.3% 
                 83.3% 
                   89% 
                 95.3% 
               
            
           
           
               
               
               
               
               
            
               
                 Crown Intensity 
                 77.9% 
                 77.1% 
                 74.9 
                 73.1 
               
            
           
           
               
               
               
               
               
            
               
                 Brightness 
                 Excellent 
                 Excellent 
                 Excellent 
                 Excellent 
               
               
                 Fire 
                 Excellent 
                 Excellent 
                 Excellent 
                 Excellent 
               
               
                 Scintillation 
                 Excellent 
                 Excellent 
                 Excellent 
                 Excellent 
               
               
                   
               
            
           
         
       
     
     The example diamonds had excellent brightness, fire, and scintillation, and intensities greater than 70% were found in the various examples. Examples 3 and 4 had large girdle thicknesses yet had excellent performance. Although the above examples are diamonds, other gemstones can be substituted for diamonds. For example, precious gemstones (sapphires, emeralds, rubies, alexandrite, etc.), semi-precious gemstones (amethyst, garnet, morganatic, etc.), and/or synthetic gemstones are also suitable candidates for the specified square cut. And the disclosed cut is especially advantageous with raw stones that have below average starting colors, as the excellent light return compensates for the inherent shortcoming. 
     While the examples of the present invention have been illustrated by the description of gemstone  100 , the girdle  200 , the crown  300 , the pavilion  400 , the jewelry  500 , the sample  600 , and/or the chevrons  700 , have been shown and described as having certain forms and fabrications, such portrayals represent only some of the possible adaptations of the claimed characteristics. While alternative examples have been described, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to the details herein. Additional advantages and modifications will readily appear to those of ordinary skill in the art. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concepts and which are intended to be encompassed by the following claims.