Physical Properties of Garnet Gemstones
A garnet is found within a group of semiprecious stones that are formed on such specific geometrical patterns as rhombic dodecahedrons and tetragonal trisoctahedrons, and even combinations of these two forms. These are minerals formed on crystalline silicate that are very common on some igneous and on metamorphic rock formations.
The different varieties of garnet display a wide variety of colors, or should we say almost all colors, all except the shades of blue. Red, orange, yellow, green, brown, black, gray, and colorless or monochromatic stones are some of the common colors. Lighter stones are usually blatant, transparent, translucent, or clear, while the darker or gloomy colors are usually opaque or better yet impervious. The hardness of this semi precious stone fluctuates and varies from 5.7 to 8. The relative densities, merging on the specific particular gravities, of such samples or specimens may be anywhere between 3.0 and 5.0. These gemstones have a resinous or a vitreous patina or luster, that are similar to the characteristics or appearance of glass. Some types and varieties display such clarity, vividness, and luminosity. Basing these semi precious stone chemically, garnets are siliceous compounds. These varieties are usually demarcated or separated by their compositions on chemicals in particular.
One of the types of garnet, usually found in shades of red, green, yellow, or brown, are the Grossularites are found mostly in chalky rock. The green parts of this rock are used as a gemstone. These are often called hyacinths and essonites or hessonites are named for cinnamon to cinnamon-brown colored types. Another type of garnet is the pyrope, are commonly and are most often used for jewelry and have fine shade of red ruby color. The pure garnet generally has no color, but all varieties have impurities such as magnesium and aluminum that produce a number of shades up to red down to the darker color to the darkest which is black. Spessartite is not a popular type of garnet due to its shade and color which is mostly and usually brownish, but make have cast of red thougth it.
Another type of garnet, the Almandine was used before in jewelry and is popularly called a Carbuncle. Only stones that are both red and transparent are considered Carbunlce. Carbunlce come in a long range of hues from red, down to deep red, to black- the color is mainly due to the larger amounts of iron aluminum silicate. Uvarovite is another type of garnet which famed for its bright emerald green color, it to is used in gemstone jewelry. Found largely in very small crystals, it mainly occurs in the Ural Mountains of Russia. Uvarovite is the rarest of all the garnet varieties, composed of calcium chromium silicate.
Garnets are mainly found in North America and also in the Alps of Sri Lanka.