The facts
What hyacinth actually is
Hyacinth is classified as zircon (variety), with the composition ZrSiO₄. It crystallises in the tetragonal system.
Colour comes from radiation-induced colour centres with trace U and Th give the orange to reddish brown, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.925–1.984. Specific gravity around 4.60–4.70. Cleavage: imperfect prismatic. Those three numbers separate it from most of what imitates it.
Where hyacinth comes from
Hyacinth is produced at Ratnapura, Sri Lanka, Mogok, Myanmar and Chanthaburi, Thailand.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How hyacinth is treated
A historic name that was also applied to orange grossular and hessonite in older literature, so provenance in antique jewellery is uncertain. Modern zircon of this colour is commonly heated; heating is standard, stable and not usually disclosed.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What hyacinth is confused with
In the trade hyacinth is most often mistaken for, or substituted by, Hessonite, Spessartine, Fire opal or Sphene.
The separation is rarely a matter of opinion: refractive index 1.925–1.984 and specific gravity 4.60–4.70 settle most of it in a minute, and magnification settles the rest.
What hyacinth is used for
Demand for hyacinth comes from jewellery and mineral collecting, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the carat or by the specimen.
Durability and care
Hyacinth is 6.5–7.5 on the Mohs scale, with imperfect prismatic cleavage.
Hardness is not the whole story. Perfect cleavage means the stone can split cleanly if struck along the wrong plane, whatever its Mohs number, so a protective setting matters more here than the hardness suggests.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What hyacinth costs
As a guide, hyacinth trades around 20–200 USD/ct.
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 hyacinth treated, and how?
A historic name that was also applied to orange grossular and hessonite in older literature, so provenance in antique jewellery is uncertain. Modern zircon of this colour is commonly heated; heating is standard, stable and not usually disclosed.
Where does hyacinth come from?
Ratnapura, Sri Lanka, Mogok, Myanmar and Chanthaburi, Thailand. Origin affects price, so we name the locality rather than the country on every quote.
Is hyacinth hard enough to wear every day?
With care. It is 6.5–7.5 on the Mohs scale, which is hard enough, but imperfect prismatic cleavage means it can split if struck at the wrong angle. Use a protective setting and avoid ultrasonic cleaning.
How much does hyacinth cost?
Indicatively 20–200 USD/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 hyacinth confused with?
Most often Hessonite, Spessartine, Fire opal and Sphene. A refractive index of 1.925–1.984 and a specific gravity near 4.60–4.70 separate it quickly.
Related stones
Looking for hyacinth?
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 hyacinth