| Garnet has been a popular gemstone for | | | | "diamond-like luster." |
| centuries due to its very good hardness (7-7.5 on | | | | Demantoid by definition is always green, with the |
| the Mohs scale) and great brilliance. Garnet also | | | | green hue caused by traces of chromium. Colors |
| has a distinctive purity of color since it is one of | | | | range from a light yellowish green (similar to |
| the very few singly refractive gemstones (along | | | | peridot) to a deep green almost the color of fine |
| with spinel and diamond). | | | | emerald. Specimens with a more intense green |
| At the same time, garnet has been regarded by | | | | are more highly valued, but the lighter stones |
| some buyers as a rather common gemstone. But | | | | display substantially more fire. You will typically find |
| while there are some common and inexpensive | | | | demantoid garnet only in smaller sizes. Specimens |
| garnets such as almandine, there are also some | | | | over one carat are uncommon and stones over 2 |
| rare and expensive ones. The rarer garnets | | | | carats count as very rare. |
| include spessartite, tsavorite and demantoid. | | | | While most garnets have been known since |
| Of these rare garnets, demantoid is by far the | | | | ancient times, demantoid garnet was not |
| rarest and most valuable. In fact demantoid is one | | | | discovered until 1853, in the Ural mountains in |
| of the rarest of all colored gemstones. Particularly | | | | Russia. The Russian deposits remained the only |
| fine demantoids can command prices of | | | | source for demantoid until a major find in Namibia |
| thousands of dollars per carat. | | | | in 1996. The Russian demantoid is now rarer, and |
| Demantoid belongs to the andradite variety of | | | | is generally more high valued. Distinctive 'horsetail' |
| garnet, which is a calcium iron silicate with a | | | | inclusions are the telltale sign of Russian |
| refractive index of 1.88-1.94. The high refractive | | | | demantoid, since these inclusions are not found |
| index makes demantoid the most brilliant of all the | | | | thus far in the Namibian material. Russian |
| garnets; and demantoid garnet has a higher | | | | demantoid nearly always contains inclusions of the |
| refractive index than sapphire and ruby. Only | | | | minerals byssolite and/or chrysotile, both of which |
| some some zircons and diamond have greater | | | | are types of asbestos. These inclusions appear as |
| brilliance. Demantoid also has remarkable dispersion | | | | feathery golden threads that tend to curve and |
| or fire that even exceeds that of diamond. | | | | resemble the tail of a horse. |
| Indeed, the very name demantoid means | | | | |