First discovered in Russia’s Ural Mountains in the mid-19th century, the demantoid garnet is an ultra-rare, velvety green variety of andradite that ranks among the most valuable of all garnets. Its name is derived from the Dutch word demant, meaning “diamond-like,” a nod to its incredible dispersion—the ability to split light into a rainbow of spectral colors—which actually exceeds that of a diamond. Its intense, lively green body color is caused by trace amounts of chromium and ferric iron, ranging from a pale yellowish-green to a highly prized deep emerald hue. What truly sets classic Russian demantoids apart, however, is a fascinating internal feature: the presence of “horsetail” inclusions made of golden chrysotile fibers that radiate outward like a firework. While inclusions usually lower a gemstone’s value, these delicate, unique patterns are highly coveted by collectors as definitive proof of the stone’s prestigious origin and natural pedigree.