The facts
What hydrogrossular actually is
The species behind hydrogrossular is grossular–hibschite series (garnet group), Ca₃Al₂(SiO₄)₃₋ₓ(OH)₄ₓ; it forms in the cubic (massive aggregate) system.
Chromium for green; iron for pink; black specks are magnetite or chromite is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.
On the instruments it reads a refractive index of 1.700–1.730 (spot ~1.72) and a specific gravity of about 3.15–3.55, with none cleavage.
Where hydrogrossular comes from
Commercial material comes from Buffelsfontein, Transvaal, South Africa, Ratnapura, Sri Lanka and Xinjiang, China.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How hydrogrossular is treated
Usually untreated, but dyed material exists. Routinely misrepresented as jade — 'Transvaal jade' is not jade of either kind; the RI and the single refraction distinguish it from jadeite and nephrite immediately.
We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.
What hydrogrossular is confused with
Watch for Jadeite, Nephrite, Serpentine, Idocrase/californite and Dyed quartzite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.700–1.730 (spot ~1.72) and specific gravity 3.15–3.55 settle most of it in a minute, and magnification settles the rest.
What hydrogrossular is used for
The trades that buy hydrogrossular are carving and sculpture, jewellery, decorative objects, architecture and interiors and mineral collecting. They do not want the same thing, and they do not pay in the same unit.
We quote each application in the unit that trade actually buys in, by the block, by the carat or by the piece.
Durability and care
Hydrogrossular is 6–7 on the Mohs scale, with none cleavage.
With no cleavage plane to worry about, the practical limit is abrasion rather than breakage, and it takes daily wear well.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What hydrogrossular costs
Expect roughly $0.50–15/ct, depending on quality.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is hydrogrossular treated, and how?
Usually untreated, but dyed material exists. Routinely misrepresented as jade — 'Transvaal jade' is not jade of either kind; the RI and the single refraction distinguish it from jadeite and nephrite immediately.
Where does hydrogrossular come from?
Buffelsfontein, Transvaal, South Africa, Ratnapura, Sri Lanka and Xinjiang, China. Origin affects price, so we name the locality rather than the country on every quote.
Is hydrogrossular hard enough to wear every day?
Yes. At 6–7 on the Mohs scale with no cleavage plane, it handles daily wear well. The practical limit is gradual abrasion rather than chipping.
How much does hydrogrossular cost?
Indicatively $0.50–15/ct. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is hydrogrossular confused with?
Most often Jadeite, Nephrite, Serpentine, Idocrase/californite and Dyed quartzite. A refractive index of 1.700–1.730 (spot ~1.72) and a specific gravity near 3.15–3.55 separate it quickly.
What is hydrogrossular used for besides jewellery?
carving and sculpture, decorative objects, architecture and interiors and mineral collecting. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for hydrogrossular?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about hydrogrossular