Identification of gemstones involves examining the gemstone's color, hardness and light intensity and the way the gemstone reflects light. According to the Gemological Institute of America, identification requires the use of a refractometer, a microscope and other equipment.Know More
Look at the brightness and intensity of the color, and note the tone and hue. Use a jeweler's loupe to see if foreign matter appears in the stone. It may appear as a bubble, crack or crystal. Place the stone under a microscope. Certain gemstones, such as emerald or diamond, show specific types of flaws that appear clearly under magnification and make identification easier.
Measure the angle of light and its speed with a refractometer. Determine the density and hardness of a stone by measuring the specific gravity using a set of premeasured liquids. A gemstone heavier than the liquid sinks to the bottom, while a gemstone lighter than the liquid floats. A gemstone whose density matches the density of the liquid hangs suspended in the middle. Measure the intensity of light passing through a gemstone, which shows up in a characteristic rainbow pattern, with the spectrometer.
Combined together, these test results compared to charts with predetermined values narrow down the type of gemstone. If no clear answer emerges, perform additional tests to supply an exact identification.
The chemical, physical and optical properties of natural gemstones are shown through measurements of light dispersion, hardness, density or specific gravity, cleavage, fracture, tenacity, refractive index and luster. These properties vary depending on the type of natural gemstone. For example, amethyst has a specific gravity of between 2.6 to 2.7, a hardness of seven, a refractive index of between 1.54 to 1.55 and a chemical formula of SiO2.Full Answer >
Onyx is most commonly colored black or black with white bands, but it is also available in red and brown. These variations are sometimes called sardonyx.Full Answer >
Obsidian is usually jet black, however, it can also be green, brown, red, blue, yellow or orange. The different colors are thought to occur due to inclusions or trace elements. It is an igneous rock that results from lava cooling rapidly and creating volcanic glass.Full Answer >
The interaction of light with matter varies based on the type of matter, the geometry of matter, the wavelength of the incident light and the light intensity. Because different parts of the electromagnetic spectrum interact differently with the same form of matter, there is no one specific interaction between light and matter.Full Answer >