Garnet

Garnet is the least useful word in the trade

One word, more than twenty mineral species, a price range running from about fifteen dollars a carat to sixty thousand. Somebody offering you a garnet has told you almost nothing. The only question worth asking is which garnet, so a Ceylon garnet listing that does not name the species is not really a listing.

They share a crystal structure without sharing a chemistry, which is why colour, hardness and price all move independently across a Ceylon garnet parcel.

Your report will name the species, not the treatment

Everywhere else on this site we tell you to read the treatment line first. Garnet is the exception, because heat, irradiation and diffusion all do essentially nothing to it. There is no commercial reason to treat a Ceylon garnet, so almost nobody does. The treatment line on the report will say none.

What the laboratory is actually doing for you here is identification. Rhodolite and purple pyrope overlap. Colour change garnet gets sold as alexandrite by the careless and the dishonest, when it is a different mineral entirely at a very different price. If that is what interests you, compare it against real alexandrite before deciding. Laboratories separate the species by refractive index, spectroscopy and magnetic susceptibility. That line on the report is the one deciding the price.

Ceylon garnet means hessonite before anything else

This is where our gravels genuinely lead. Hessonite comes principally from Sri Lanka, which produces the finest warm cinnamon colour in the world. Indian and Tanzanian stones run darker. Our gem gravels have given up hessonites of several hundred carats.

Look inside one and you will see a swirling, treacly texture the trade calls scotch and water. It is not a flaw. It is the signature of the variety, caused by a microstructure unusual among faceted gems, so a hessonite without it is worth a second look. We also produce almandine, rhodolite, spessartine and the scarce colour change material, all out of the same river gravel as the sapphire.

Hessonite is gomed in Vedic astrology, one of the nine stones of the navaratna, which drives a great deal of Ceylon garnet demand from India. We can tell you the species, the origin and the weight. We do not make claims about what a stone will do.

How durable is it depends entirely on which one

The group spans six and a half to seven and a half on the Mohs scale, so the answer changes with the species. Almandine, pyrope, rhodolite, spessartine and tsavorite all sit at seven or above, taking daily wear without much thought.

Demantoid and some hessonite fall below seven, which means household dust alone can scratch them over time. Those want a bezel or another protective setting in a ring, plus hand cleaning rather than an ultrasonic. Warm soapy water and a soft brush suits every garnet. Store them away from your sapphires, which will scratch them.

What it costs and where the value hides

Red garnet is among the most affordable fine coloured stones on earth, which is exactly why the group has a reputation problem. Meanwhile a fine tsavorite above a carat runs past a thousand dollars. Demantoid outprices most sapphire.