nyuuzyou/wikis huggingface dataset:
Lepidolite

== Description ==
A rose-violet color mica with shiny hexagonal plates. Lepidolite deposits are found in the Czech Republic, Ural Mountains, South Africa, Brazil (Minas Gerais), and the U.S. (California, South Dakota, New Mexico). Lepidolite is a potassium lithium aluminum silicate. The translucent mineral is usually lilac or rose in color but may also be white, gray or yellow. Lepidolite is sometimes used as a in glass and ceramic production but it can release fluorine gas resulting in bubbles.
== Synonyms and Related Terms ==
lithia mica; lepidolita (Esp.); lepidoliet (Ned.); lepidolit (Pol.); lepidolite (Port.); Lepidolit (Deut.)
== Risks ==
* Skin contact may cause burns. 
* Inhalation and ingestion may cause irritation of membranes
== Physical and Chemical Properties ==
* Monoclinic system usually in hexagonal plates. 
* Cleavage is perfect in one direction. 
* Luster = pearly. 
* Streak = colorless. 
* Translucent to transparent.
Composition 	K2Li3Al4Si7O21(OH,F)3
Mohs Hardness	2.5 - 4.0
Melting Point	1170 C
Density 	2.8-3.3 g/ml
== Resources and Citations ==
* Mineralogy Database: Lepidolite
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* Robert Fournier, Illustrated Dictionary of Practical Pottery, Chilton Book Company, Radnor, PA, 1992
* Encyclopedia Britannica, http://www.britannica.com Comment: "lepidolite." (Accessed 8 May, 2002). color photo
* C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
* Wikipedia: http://en.wikipedia.org/wiki/Lepidolite (Accessed Sept. 7, 2005)
* Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
Category:Materials database
Letona

== Description ==
A strong, lustrous fiber obtained from the leaves of the Agave letonae plant. Letona is cultivated in El Salvador. Similar to henequen, letona fibers are used for coffee bags, canvas, and twine (Cook 1984).
==Resources and Citations==
* G.Cook, Handbook of Textile Fibres:I. Natural Fibres, 5th edition, Merrow Publishing Co., Durham, England, 1984..
Category:Materials database
Letterpress ink

== Description ==
A thick, pasty ink used on letterpress rollers. Letterpress inks produce a slightly raised image that typically dries by oxidation.
== Synonyms and Related Terms ==
half-tone ink
==Resources and Citations==
* Boise Cascade Paper Group, The Paper Handbook, Boise Cascade, Portland OR, 1989
* Luis Nadeau, Encyclopedia of Printing, Photographic, and Photomechanical Processes, Atelier, New Brunswick, 1997
Category:Materials database
Lettuce oil

== Description ==
A semidrying oil expressed from the seeds of lettuce plants (Lactuca sativa and Lactuca serriola) native to the Mediterranean region. Lettuce oil contains linoleic acid (51.1-56.9%), oleic acid (37.6-40.2%), palmitic acid (1.9-4.3%), and stearic acid (1.3-4.1%) (Serpico and White 2000). The oil may have been used in ancient Egypt for cooking.
== Synonyms and Related Terms ==
Lactuca sativa; Lactuca serriola; aceite de lechuga (Esp.); olio di lattuga (It)
==Resources and Citations==
* M.Serpico, R.White, "Oil, fat and wax" in Ancient Egyptian Materials and Technology, P.Nicholson, I.Shaw (eds.), Cambridge University Press, 2000, p. 390-429.
Category:Materials database
Leucine

== Description ==
An essential amino acid that was first discovered in 1819. Leucine is a water-soluble amino acid that can be purified from zein, hemoglobin, and edestin to produce a white crystalline powder. Leucine is necessary for growth and maintaining the nitrogen balance.
[[[SliderGallery rightalign|leucine.jpg~Chemical structure]]]
== Synonyms and Related Terms ==
LEU: alpha-amino-gamma-methylvaleric acid; alpha-aminoisocaproic acid
== Risks ==
* Sensitive to light and moisture. 
* Potential teratogen. 
* Fisher Scientific: MSDS
==Physical and Chemical Properties==
Soluble in water. Slightly soluble in ethanol. Insoluble in ether.
Composition 	C4H9CH(NH2)COOH
CAS 	(l) 61-90-5; (d) 328-38-1
Density 	1.293 g/ml
Molecular Weight	mol. wt. = 131.17
==Resources and Citations==
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 5475
* The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
Category:Materials database
Leucocratic rock

== Description ==
Igneous rock containing 65 to 95% of felsic minerals, such as feldspathoids (nepheline and leucite), muscovite, and corundum. Because felsic minerals lack iron and magnesium, they are generally light in color and consequently are referred to as leucocratic.
== Synonyms and Related Terms ==
rocha leucocrática (Port.)
==Resources and Citations==
* José Delgado Rodrigues, LNEC, Submitted information, 2009
* Encyclopedia Britannica, http://www.britannica.com Comment: Leucocratic rock
Category:Materials database
Lexan

== Description ==
[GE Structured Products] A registered trademark for a thermoplastic polycarbonate (PC) sheet that was first marketed in 1959. Lexan sheets are clear, strong, have good weather resistance and are often used for optical products, optical discs, sunlight panels, etc. They have a lower softening temperature than Plexiglas and do not fracture as easily. Most of the Lexan sheets are UV stabilized to provide a resistance to yellowing that is similar to acrylic sheets. Lexan can be used as window and door glass. PC laminates are widely used in banks, embassies, and public places for protective windows, aircraft hatch covers, lighting equipment, industrial safety panels and bulletproof glass.
The manufacturer lists the following cleaners as compatible with Lexan sheets: Freon, VM&P naphtha, Windex with Ammonia D [Dracket Products], Top Job [Proctor & Gamble], Joy [Proctor & Gamble], Palmolive Liquid [Colgate Palmolive] and Formula 409 [Clorox Co.],
== Synonyms and Related Terms ==
polycarbonate sheet
Similar products: Makrofol [Bayer]; Makrolon [Bayer]; PC1000 [Quadrant]; Tuffak [Arkema]
== Risks ==
* Polycarbonate is derived from and releases bisphenol A upon degradation via hydrolysis. 
* Bleach (sodium hypochlorite) and alkali cleaners catalyze the release of bisphenol A (BPA) from polycarbonate (Hunt 2003, Koehler 2003).
== Physical and Chemical Properties ==
* Soluble in benzene, gasoline, acetone, carbon tetrachloride.
* Melting point is 212 C
* Flame retardant and impact resistant without any additives
* Lexan Technical Manual
==Resources and Citations==
* GE: Lexan Website
* Molly McGath, AIC Plastics Panel, Contributed information, 2020.
* Hunt, PA; Kara E. Koehler; Martha Susiarjo; Craig A. Hodges; Arlene Ilagan; Robert C. Voigt; Sally Thomas; Brian F. Thomas; Terry J. Hassold (2003). "Bisphenol A Exposure Causes Meiotic Aneuploidy in the Female Mouse". Current Biology. 13 (7): 546–553. doi:10.1016/S0960-9822(03)00189-1. PMID 12676084
* Koehler, KE; Robert C. Voigt; Sally Thomas; Bruce Lamb; Cheryl Urban; Terry Hassold; Patricia A. Hunt (2003). "When disaster strikes: rethinking caging materials". Lab Animal. 32 (4): 24–27. doi:10.1038/laban0403-24. PMID 19753748. Archived from the original on 2009-07-06. Retrieved 2008-05-06.
* Collin, S.; Bussière, P. -O.; Thérias, S.; Lambert, J. -M.; Perdereau, J.; Gardette, J. -L. (2012-11-01). "Physicochemical and mechanical impacts of photo-ageing on bisphenol a polycarbonate". Polymer Degradation and Stability. 97 (11): 2284–2293. doi:10.1016/j.polymdegradstab.2012.07.036.
* "Pollution Database". pollution.unibuc.ro. Archived from the original on 2017-12-29. Retrieved 2016-11-14.
Category:Materials databaseCategory:MWGCategory:GlazingCategory: Board/Panel, Plastic
Ley

== Description ==
Common name for lye (sodium hydroxide and potassium hydroxide) used prior to the 1800s when chemical compound names were standardized (Schur 1985).
== Synonyms and Related Terms ==
lye
==Resources and Citations==
* Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
Category:Materials database
Libethenite

== Description ==
A rare copper phosphate hydroxide mineral (Cu2(PO4)(OH)). Libethenite was identified as a corrosion product on German bronzes that were in a burial environment adjacent to bones.
==Physical and Chemical Properties==
* Description = light to dark green slender crystals
* Fracture = irregular
* Luster = resinous, waxy
* Streak = light green
* Hardness = 4
* Density = 3.97 g/ml
==Resources and Citations==
* W.von Geilmann, K.Meisel "Rontgenographische Untersuchungens Methoden in der Vorgeshichtsforschung: Libethenite, ein Mineral der Patinabidung" Nachrichtenblatt fur Deutsche Vorzeit 18:208-212, 1942.
* M.Fabrizi,H.Ganiaris,S.Tarling, D.Scott, 'The Occurrence of Sampleite, a Complex Copper Phosphate, as a Corrosion Product on Copper Alloy Objects from Memphis, Egypt', Studies in Conservation, 34, 45-51, 1989. (Note: sampleite is a different kind of copper phosphate)
* Wikipedia: Libethenite Accessed Dec 2022
* Mindat: Libethenite
Category:Materials database
Library paste

== Description ==
A thick, white, water soluble, sweet-tasting adhesive that was commonly used in libraries and schools for paper and cardboard. Library paste is usually made from dextrin, a water-soluble modified starch. Some formulations may contain starch, gum arabic and bone glue. Library paste was sold in jars, with an applicator attached to the inside of the lid. By the end of the 20th century, library paste was no longer commonly used and often difficult to obtain.
==Resources and Citations==
* Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* Irving Skeist, Handbook of Adhesives, Van Nostrand Reinhold Company, New York, 1977
* Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000
Category:Materials database
Lichen

== Description ==
Any of about 18,000 thallophytic organisms composed of an algae and a fungus growing in a symbiotic relationship on a solid substrate, such as a rock. Lichen have been used since ancient times as a source of food, medicine and dyes. Lichens grow relatively slowly (about 0.1 - 10 mm per year). Algae perform phtosynthesis producing carbohydrates and vitamins while the fungi absorb water vapour and provide a protective environment for the delicate algae. Their composite body is called a thallus and is classified as:
* squamulose: small, flat scales that do not adhere tightly to substrate
* crustose: flat, firmly attached to substrate
* foliose: leaf-like lobes, attached in the center to substrate by clusters of hyphae (rhizones); may reach several feet in diameter
* fructicose: plant-like growth attached at one point or cluseter called a holdfast
Additionally, Natural dyes have been extracted from lichens for several hundred years. Lichen dyes produces red, blue, yellow, purple and brown colors on wool. Many of these dyes are strong-acid base indicators, such as litmus. 
* See archil, cudbear, and litmus.
== Resources and Citations ==
* ICOMOS-ISCS: Illustrated glossary on stone deterioration patterns
* Wikipedia: Lichen at https://en.wikipedia.org/wiki/Lichen (June 2020)
* Encyclopedia Britannica, http://www.britannica.com Comment: "lichen" [Accessed April 26, 2002].
* G.Caneva, M.P.Nugari, O.Salvadori, Biology in the Conservation of Works of Art, ICCROM, Rome, 1991
Category:Materials database
Lichen dyes

== Description ==
Natural dyes have been extracted from lichens for several hundred years. Lichen dyes produces red, blue, yellow, purple and brown colors on wool. Many of these dyes are strong-acid base indicators, such as litmus. 
* See archil, cudbear, and litmus.
== Synonyms and Related Terms ==
colorantes de líquenes (Esp.); corantes de líquenes (Port.)
== Resources and Citations ==
* R.J. Adrosko, Natural Dyes in the United States, Smithsonian Institution Press, Washington, DC, 1968
* Thomas Gregory, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 3rd ed., 1942
* John and Margaret Cannon, Dye Plants and Dyeing, Herbert Press, London, 1994
Category:Materials database
Licorice

== Description ==
A fugitive brown extract obtained from the roots of the Spanish licorice plant, Glycyrrhiza glabra native to southern Europe. Licorice is composed of a glycoside, an estrogenic hormone, sugar, and a saponin. It is water soluble and forms a sticky, viscous fluid. The saponin extract from licorice is used in fire extinguishers and it is added to fiber-based insulated building boards as an insect repellent. Licorice was sometimes added to bister to improve its working properties. The brown liquid was also used as a thin, transparent glaze for paintings.
== Synonyms and Related Terms ==
Glycyrrhiza glabra; sweet root; Spanish licorice; Spanish juice
==Physical and Chemical Properties==
Soluble in water.
==Resources and Citations==
* R.White "Brown and Black Organic Glazes, Pigments and Paints" National Gallery Technical Bulletin, 10:58-71, 1986.
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 4514
* Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000
Category:Materials database
Light Damage Slide Rule

== Description ==
A tool developed by the Canadian Conservation Institute in 1989. The Light Damage Slide Rule is used to compare the effects of varying light intensities and exposure times on color fading. Based on the colorant composition and their ISO lightfastness ratings, the slide rule shows estimates of fading times and their potential reduction when light intensities or exposure times are decreased.
==Resources and Citations==
* "A Light Damage Slide Rule" CCI Notes N2/6, Canadian Conservation Institute, Ottawa, Sept. 1989. 
* S.Michalksi, "Towards Specific Lighting Guidelines" Preprints of the 9th Triennial Meeting, ICOM Committee for Conservation, Dresden, 1990, pp. 583-588.
Category:Materials database
Light emitting diode

== Description ==
A small, solid, semiconducting crystals that produces light from electricity. Light emitting diodes, or LEDs, were first invented by General Electric in 1962. The light is emitted at a very narrow range of wavelengths by the transition of electrons between energy levels. These early red light emitting LEDs emitted low levels of light and were used in displays, sensors, and electronic equipment. In the 1990s, blue (450 nm), blue-green, violet, ultraviolet and and white LEDs were developed by Shuji Nakamura in Japan based on InGaN/AlGaN. These blue LEDS produce a light density which is about 100 times higher. These GaN based LEDs are being used for traffic lights, car headlights, TV displays, copiers, and scanners. Because of their efficiency, these LEDs provide 50-70% energy savings when used to replace indoor lightbulbs and fluorescent tubes.
== Synonyms and Related Terms ==
LED
==Physical and Chemical Properties==
Lifetimes estimated at 10,000 hours
==Resources and Citations==
* GE Lighting: www.gelighting.com/na/institute/ul_last100.html - gives date of first diode as 1962
* Eurotechnology.com on Blue LEDs at http://www.eurotechnology.com/bluelaser/blueslide15.html
Category:Materials database
Light filter

== Description ==
A material that selectively transmits specific wavelengths thereby producing a restricted light spectrum from a full spectrum source. Light filters are available in several types, including color, reflective, ultraviolet, and neutral density filters. Color filters are typically made from glass of plastic and contain compounds that absorb specific wavelengths, or colors. Reflective filters typically have a reflective coating on a glass substrate that reflects the unwanted wavelengths. Reflective filters have sharp-edged filter bands and are often used for precision wavelength selection. Ultraviolet (UV) filters block ultraviolet radiation while letting the visible wavelengths pass. Neutral density filters provide a constant attenuation to decrease the intensity of all wavelengths.
== Synonyms and Related Terms ==
light filtration; optics filter; optical filter; color filter; colour filter (Br.); neutral density filter; reflective filter; ultraviolet filter; UV filter; Fotografisches Filter (Deut.); optisch filter (Ned.);
==Resources and Citations==
* Olympus Microscopy: www.olympusmicro.com (Accessed Sept. 28, 2005)
* Wikipedia: http://en.wikipedia.org/wiki/Filter_%28optics%29 (Accessed Sept. 28, 2005)
Category:Materials database
Light opal

== Description ==
An opal with pale iridescent colors. Light opals typically have bluish or greenish tones but may also show oranges and pinks. The colors depend on the crystal size within the stone. When the particles are small, some purple can be seen. Medium sized particles diffract green and larger particles show red. Light opals with an opaque, milky background are called white or milk opals. Most light opals come from Australia (Coober Pedy and Mintabie mines).
== Synonyms and Related Terms ==
white opal; milk opal
==Physical and Chemical Properties==
* Massive with no crystalline structure. 
* Cleavage=none 
* Luster = vitreous to pearly. 
* Fracture = conchoidal. 
* Streak = white 
* Iridescent. 
* Fluorescence = usually white or pale green, some samples phosphoresce
Mohs Hardness 	5.5-6.5
Density 	2.15 g/ml
Refractive Index	1.42-1.47
==Resources and Citations==
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* Wikipedia: http://en.wikipedia.org/wiki/Opal (Accessed Oct. 12, 2005)
* Yasukazu Suwa, Gemstones: Quality and Value, Volume 1, Sekai Bunka Publishing Inc., Tokyo, 1999
* Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003
Category:Materials database
Light red

== Description ==
An orangey-red synthetic pigment composed of red iron oxide. Light red is obtained by either roasting yellow ocher or as a by-product from steel-mill waste. The permanent, opaque pigment has a bright red color with good hiding and tinting properties. Light red is used in artists' paints, marine paints, metal primers, and as a filler in rubbers and plastics. The name 'light red' has also been applied to color blends made from red iron oxide and gypsum.
== Synonyms and Related Terms ==
iron oxide red; red iron oxide; Pigment Red 101; CI 77419; rouge anglais (Fr.); rode oker (Ned.); vermelho claro (Port.); English red; Prussian red; colcothar; morelle salt; Persian red; Antwerp red; Indian red;
== Risks ==
* No significant hazards.
==Physical and Chemical Properties==
Composition	Fe2O3
CAS 	1309-37-1
==Resources and Citations==
* Thomas Gregory, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 3rd ed., 1942
* Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
* Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
* Monona Rossol, The Artist's Complete Health and Safety Guide, Allworth Press, New York, 1994
Category:Materials database
Light waves

== Description ==
Electromagnetic radiation can be simplified by considering the energy in the form of waves. Each wave can then be characterized by its amplitude and wavelength. The wavelengths for visible light extend from about 400 to 700 nanometers.
== Synonyms and Related Terms ==
Lichtwellen (Deut.)
==Resources and Citations==
* G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
Category:Materials database
Light white

== Description ==
An unstandardized name for a white pigment, usually thought to be silver nitrate. Light white is described as the precipitate that is formed when silver is dissolved in nitric acid, then washed and dried. This precipitate, silver nitrate, was also sold under the names of white silver and Ackermanns white, as a watercolor pigment. Silver nitrate, however, turns dark on exposure to air and is not considered permanent.
==Resources and Citations==
* Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
* R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
Category:Materials database
Lightbulb

== Description ==
An illumination source produced by a filament heated to incandescence by an electric current. Light sources, in this dictionary, are called a lamps. 
See also electric lamp, fluorescent lamp, and incandescent lamp.
== Synonyms and Related Terms ==
light bulb; lamp
See Electric lamp, Fluorescent lamp, Incandescent lamp and Light emitting diode.
== Additional Images ==
File:Lightbulbwp2.jpg|Drawing of a lightbulb
File:Incand.lamp_Edison_nps.gov.jpg|Edison Incandescent Lamp
File:Edison_filament.diag_nps.gov.jpg|Drawing of a Light Bulb
==Resources and Citations==
* Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
Category:Materials database
Lightbulb filament

== Description ==
Incandescent light bulbs used electricity to heat a metal wire, called a filament, to produce visible light. See attached image. The filament is housed in a sealed, oxygen-free chamber to prevent combustion. Tungsten was used because it has a very high melting point. these bulbs were inexpensive and easy-to-use, but eventually gave way to other, more energy efficient technologies, such as fluorescent, then LED lamps.
== Synonyms and Related Terms ==
lightbulb filament
Category:Materials database
Lightfastness

== Description ==
The ability of a color to maintain its tone and hue when exposed to daylight. Ultraviolet radiation in sunlight can irreversibly break chemical bonds, thus altering the composition, and thus color absorption capabilities, of many organic colorants. Lightfastness is used to describe colors used in artists paints, industrial paints, printing inks and textile dyes. Lightfastness tests can be conducted with either direct exposure to sunlight or simulated exposure in an indoor chamber with an artificial light source. The lightfastness of a color can be affected by the quantity and type of binding medium.
== Synonyms and Related Terms ==
Lichtechtheit (Deut.); tenue à la lumière (Fr.); résistance à la lumière (Fr.); colorfastness
==Resources and Citations==
* J.Reilly, D.Nishimura, E.Zinn, Assessing Long-Term Environmental Effects on Library and Archives Collections, New Tools for Preservation, The Commission of Preservation and Access, Washington DC, 1995
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
* Hoechst Celanese Corporation, Dictionary of Fiber & Textile Technology (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990
Category:Materials database