The chromium garnet, uvarovite, generally is too poor in quality for cutting. Uvarovite crystals, which are emerald green in color, occur in only small sizes. They are found mostly in Russia, Finland, and California.
Grossular varies in color. It occurs chiefly in some shade of red, green, yellow, or brown, depending on the impurities present. When pure, grossular is colorless. A kind of grossular called hessonite has an attractive cinnamon color, and it is found mainly in Ceylon. Because of its color it can easily be confused with spessartine, which it closely resembles.
Andradite, a very common garnet, usually is found in shades of red, black, brown, yellow, or green. Some types of gem andradite have special names for different colors: topazolite, yellow; demantoid, green; and melanite, sparkling black. The very valuable demantoid is found in Russia and Italy.
VARIETIES: Grossular: Colorless, green, amber, brownish yellow, rose Hessonite: Cinnamon colored Pyrope: Deep red Rhodolite: Rose red and purple Almandine: Deep red Spessartine: Brownish red to orange Andradite: Yellow, greenish yellow, emerald green, brownish red, brownish yellow, brown, black Topazolite: Yellow to greenish Demantoid: Grass green to emerald green Melanite: Black Uvarovite: Green
JADE
The name jade is applied to two unrelated minerals—nephrite and jadeite—that have somewhat similar characteristics.
Jadeite, the rarer of the two, is a sodium aluminum silicate that belongs to a group of rock-forming minerals known as pyroxenes. Its color varies from white to emerald green and many other colors. Jadeite is highly prized, and when it occurs as emerald green it is considered one of the most valuable gemstones. This kind of jade is found in many places, but the most important occurrence is in Upper Burma. Nephrite, a more common species, is a calcium magnesium iron silicate belonging to a group of rock-forming minerals known as amphiboles. The color varies from white to a dark spinach green and black. Among the places where nephrite occurs are New Zealand, Turkestan, Siberia, Alaska, China, Silesia, and certain parts of the western United States, notably in Wyoming and California.
This emerald green jadeite carving, dating from the Ch’ien-lung period (1736-1795), stands 6½ inches without the base. It was given to the Smithsonian as part of the Maude Monell Vetlesen collection.
Jade is not particularly hard (6½), but it is very tough, and this characteristic makes it an excellent material for carving. Even when subjected to punishing usage, jade resists chipping and wear. It was used for making tools and weapons by primitive peoples who lived in what is now Mexico, Switzerland, France, Greece, Egypt, Asia Minor, and in other places. The jade implements fashioned by these peoples have survived well the ravages of time.