We have compiled a listing of the scientific characteristics of many different gemstones. This is a chart that displays at a glance the important information about each classification of gemstone and it's members. Enjoy!
This is a fairly comprehensive listing of gemstones with their specific gravity, Mohs hardness, index of refraction and gemstone family classification in alphabetical order. We color coated them to help differentiate between them (these are approximations and subject to error).
Specific Gravity: Specific gravity is the number of times heavier a gemstone of any volume is than an equal volume of water; in other words, it is the ratio of the density of the gemstone to the density of water. For all gemstones listed in this table there is a scientifically determined specific gravity. You can use the specific gravity and a couple simple measurements to estimate the carat weight of a stone. We have created a calculator that makes a gemstone carat weight estimation using this principle.
Mohs Hardness: Hardness can be tested through scratching. A mineral can only be scratched by a harder substance. Therefore, a relative scale can be established to account for the differences in hardness simply by seeing which mineral scratches another. That is exactly what French mineralogist Friedrich Mohs proposed almost one hundred and seventy years ago. The Mohs Hardness Scale starting with talc at 1 being the softest and ending with diamond at 10 hardest, is universally used around the world as a way of distinguishing minerals. Simply put - the higher the number, the harder the mineral.
Index of Refraction: All materials refract light, ie alter its angle. The amount by which light is refracted is an important feature of every gemstone. The measure of a material's refractivity is known as its index of refracton (R.I.). Without going too deeply into physics, light travels at different speeds through different media. When light passes from one medium to another, its path is altered (bent) and it is said to be diffracted.
Gemstone Family Classification: The gemstones listed here show every color in the rainbow. Even with such variety of colors, patterns and shapes - they can be broken down into 16 different families based on their chemical composition.