Last updateWed, 25 Mar 2020 1pm

All tail, no horse

Jarrett HorsetailDemantoid garnets are an uncommon lot and highly collectible, not just for their rarity, but also for their dazzling color. This garnet family member is an andradite mineral rich in calcium and iron. A chromium substitution causes the iconic demantoid green tint.

What have we found here?

In general, garnets have been around for thousands of years - but the demantoid variety not so much. Late in the 19th century, Russian miners picking around the Ural mountain range came upon these remarkable highly refractive bits - not at all like the garnet of any color they were used to seeing. The name demantoid stuck as a reference to its diamond like high dispersion.

Russian jeweler to the aristocracy Carl Fabergé made good use of the sparkly bits, incorporating them into his regal suites until the austerity of the Russian Revolution put the kibosh on anything fun, including wearing jewelry.

Those were some dark days. Fortunately they are in everyone’s rearview mirror, and the green stones are back in vogue everywhere. In the 1970s to 1990s, a greater hoard was discovered in Russia’s Bobrovka River region. In the late ‘90s a significant Namibian find was located in what is now known as the “Green Dragon” mine.

Tell-tale tail

Like many gemstones, certain tell-tale inclusions help establish the identity of a stone and many times its provenance. Russian demantoid often contained curious chrysotile inclusions dubbed ‘horsetails’ as they were thought to mimic the equine’s plumy back end. They are considered diagnostic for identification of a demantoid garnet since they do not appear in any other gemstone. Thought to be the sole identifier of Russian demantoid, horsetail included demantoid from Namibian has yet to be found bearing these rare inclusions.

Many collectors and sellers believe that horsetail inclusions in demantoid goods increases their value and that may be true since it is part of the gemstone’s story. While some inclusions in gemstones are undesirable, and detract from their overall beauty - these inclusions are attractive in their own right. Seen through a microscope, the horsetail inclusions appear like golden threads that may fan out like the spray of an actual horse’s tail.

Jarrett dragonflyWhat to collect

So, while die-hard collectors seek out demantoid garnet with its iconic horsetail inclusions, all demantoid is worthy of adulation. According to AJS Gems, a leading loose gemstone purveyor based in Bangkok, there are plenty of reasons to collect this jewel. “The rarest and most valuable demantoid comes from Russia, and for serious gem investors only the Russian material is worth notice.”

But for jewelry fans drawn to the stones’ extravagant dispersion and distinct color, there are still plenty of other sources to look for this jazzy jewel. Keep in mind; it is rarely found in large carat sizes whatsoever. AJS explains. “Demantoid garnet is found mainly in small sizes, with most stones less than 1 carat. Gems over 2 carats are considered extremely rare, and market prices reflect that. Among the rare garnets, fine demantoid is substantially more valuable than tsavorite or spessartite.”

Russian, Namibian or Madagascar; demantoid garnet from any of these locales are sure to attract a collector looking for a hard to find and breathtakingly fiery gemstone.

Award winning trade journalist and gemologist Diana Jarrett is a Registered Master Valuer Appraiser and a member of the Association of Independent Jewellery Valuers (AIJV). She’s a popular speaker at conferences and trade shows. Jarrett writes for trade and consumer publications, online outlets, her blog: Color-n-Ice, and www.jewelrywebsitedesigners.com. Contact her at This email address is being protected from spambots. You need JavaScript enabled to view it., visit her website at www.dianajarrett.com, and follow her on Facebook and Twitter (Loupey).