African Hessonite Garnet

Buying this stone

Where it came from, what its weight band is for, and what to check before any money changes hands.

The deposit

East Africa, principally Tanzania and Kenya, has become the main supply of hessonite reaching the Indian market, alongside the traditional Sri Lankan source. Origin does less work in hessonite than in ruby or sapphire, and it is worth saying so plainly rather than inventing a distinction: grossular garnet is chemically consistent enough that colour saturation and transparency, not the country on the invoice, are what set the price. What East Africa reliably contributes is size, because the deposits yield clean crystals large enough to cut double-digit stones.

This stone

At 17.95 carats this is a large hessonite by any measure, and Gomed is a stone where that matters unusually much. Astrological prescription for Rahu is often written at a high weight, and hessonite is a comparatively inexpensive species per carat, so buyers who could not reach a prescribed weight in sapphire or ruby can reach it here. The difficulty at this size is transparency: a big hessonite has a long light path, and the treacly swirl that is normal in the species turns from character into murk if the material is not clean enough to carry it.

Treatment

Garnet is one of the very few gemstones that is essentially never treated anywhere in the trade. There is no established heat, diffusion, oiling or filling practice for hessonite, so a seller should be able to say untreated without hedging, and this one is. That makes hessonite one of the most straightforward Navratna stones to buy honestly. What replaces treatment as the risk here is substitution, since several cheaper materials reach a similar honey orange.

The report

No report is held for this 17.95 cts hessonite garnet stone yet, and we would rather say that than name a laboratory that has not seen it. We will submit it to IGI or IIGJ before purchase on request.

Before you pay

• Hold it to a light and find the roiled, heat-shimmer texture inside. It is diagnostic of hessonite and its absence should make you ask questions.
• Look for round gas bubbles, which mean glass rather than garnet, and which no natural stone contains.
• Check the stone face up at arm’s length. At this size a colour that is lively in the hand can still read muddy across a room.

Read next

Gomed, the hessonite covers the material itself and what gets sold in its place. How to buy a coloured stone covers pricing, treatment and reports.

Written by Kamal Kishore Agarwal, founder and gemmologist, Gem-A qualified, buying in Johari Bazaar since 2008.