INPUT ARTICLE: Article: There are a few identification tests that you may wish to avoid if you need to preserve the gemstone in its current state. This includes hardness, streak, and cleavage tests. Some stones are physically harder than others, and hardness is usually measured by the Mohs' Scale. Use the various substances provided in a hardness kit to scratch the surface of the gemstone. If the stone can be scratched, it is softer than the substance you scratched it with. If the stone cannot be scratched, it is harder than the substance. To test streak, drag the stone across a ceramic plate. Compare the streak left behind to the streaks illustrated on a streak chart. "Cleavage" refers to the way a crystal breaks. If there are chips along to surface, examine the area inside the chips. If not, you will need to strike the gemstone hard enough to break it. Ask yourself if the area is rounded like rings on a seashell (conchoidal), straight like steps, granular, splintery, or uneven. Optical phenomenon only occurs inside certain stones. Depending on the stone, you might observe color change, asterism, bands of moving light, or more. Check for optical phenomena by passing a pen light across the stone's surface. Color change is one of the most important optical phenomena to look for, and every stone should be checked for color change. Look for changes in color between natural light, incandescent light, and fluorescent light. Luster refers to the quality and intensity with which a surface reflects light. When testing for luster, reflect light off the portion of the gemstone with the best polish. To check for luster, turn the stone, allowing light to reflect off its surface. View the stone with the naked eye and with a 10x loupe. Determine if the stone looks dull, waxy, metallic, shiny (adamantine), glass-like (vitreous), greasy, or silky. The manner in which a stone separates white light into its spectral colors is called dispersion, and the visible display of dispersion is called fire. Examine the amount and strength of this "fire" to help identify the stone. Shine a penlight through the stone and examine the fire inside the stone. Ask yourself if the fire is weak, moderate, strong, or extreme. You can test refractive index (RI) using a refractometer. Using this device, you'll be able to measure the degree at which the course of light is altered within the stone. Each gemstone has its own RI, so discovering a sample's RI can help you figure out what sort of stone it actually is. Place a small bead of RI fluid on the metal surface of the refractometer near the back of the crystal hemicylinder (the window on which the stone will sit). Place the stone facet face down on the fluid dot and slide it toward the middle of the hemicylinder crystal using your fingers. Look through the viewer lens without magnification. Continue looking until you see the outline of a bubble, then look at the bottom of this bubble. Take the reading from there, rounding the decimal to the nearest hundredth. Use the magnifying lens to take a more specific reading and round it to the nearest thousandth. Birefringence is related to RI. While doing birefringence test, you will turn the gemstone on the refractometer six times throughout the observation period and note the changes. Perform a standard RI test. Instead of keeping the stone still, gradually turn it 180 degrees, making each separate turn about 30 degrees. At each 30 degree mark, take a new RI reading. Subtract the lowest reading from the highest to find the stone's birefringence. Round it to the nearest thousandth. Use this test on translucent and transparent stones. You can determine whether the stone is only singly refractive (SR) or doubly refractive (DR) to help identify it. Some stones can also be classified as aggregate (AGG). Turn on the light of a polariscope and place the stone face down on the lower glass lens (polarizer). Look through the top lens (analyzer), turning the top lens until the area around the stone looks darkest. This is your starting point. Turn the analyzer 360 degrees and watch how the light around the stone changes. If the stone appeared dark and stays dark, it is likely an SR. If the stone starts light and stays light, it is likely AGG. If the lightness or darkness of the stone changes, it is likely DR.

SUMMARY: Ask yourself if damage tests are appropriate. Check optical phenomena. Look at the luster. Observe the gemstone's dispersion. Determine the refractive index. Consider testing the birefringence, as well. Check for single or double refraction.

INPUT ARTICLE: Article: Injury is another common reason that people develop lower back issues. Protect your back while lifting items by using the proper methods of lifting that avoid back strain. This is important even when you are young, as minor injuries that do not affect you immediately may make you more susceptible to more serious injuries later on. Approach an object you intend to lift and stand as close as possible to it. Spread your feet apart to provide yourself a wide base of support. Essentially, position yourself so that you're able to bend at your knees and grip the object either between or just in front of your feet. Never position yourself in a way that will require you to bend at your waist or at your back. After safely positioning and gripping and object, tighten and maintain the flex of your stomach muscles as you lift an object. Always raise and lower an object straight up and down, holding it close to your body and using the muscles in your legs. Again, do not bend or twist when lifting, lowering, or carrying a heavy item. When setting something down, do so with a squatting motion, keeping your back straight and using the muscles in your legs to bare the load. Get help lifting anything that you are not absolutely certain you can lift safely on your own. If an item is awkwardly shaped, or is heavier than items you commonly lift with ease, have someone else help you lift it. Whenever available, use dollies or other tools and machines to help you move heavy objects.

SUMMARY:
Prevent back injuries by lifting carefully. Position yourself closely to heavy objects. Lift and lower straight up and down. Get help lifting dangerous objects.