The facts
What hydroxylherderite actually is
Mineralogically, hydroxylherderite is herderite–hydroxylherderite series — CaBe(PO₄)(OH), crystallising in the monoclinic system.
The colour is caused by traces of Fe and Mn giving pale straw-yellow, greenish-yellow and occasionally lilac. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.592–1.621, and the specific gravity sits near 2.95–3.02; cleavage is imperfect {110}.
Where hydroxylherderite comes from
The recognised sources are Golconda and Linópolis, Minas Gerais, Brazil, Virgem da Lapa, Minas Gerais, Brazil, Mount Apatite, Auburn, Maine, USA and Erongo, Namibia.
Origin affects price in this material, so we name the locality on every quote rather than the country. "African" or "Asian" tells a buyer nothing.
How hydroxylherderite is treated
Untreated. Most material sold as 'herderite' is the hydroxyl-dominant species; true fluorine-dominant herderite is rare. Strong blue fluorescence under shortwave UV is characteristic.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What hydroxylherderite is confused with
The usual confusions are Beryllonite, Apatite, Brazilianite and Phenakite.
The separation is rarely a matter of opinion: refractive index 1.592–1.621 and specific gravity 2.95–3.02 settle most of it in a minute, and magnification settles the rest.
What hydroxylherderite is used for
Hydroxylherderite is bought by mineral collecting and jewellery — and each of those trades wants a different form of the same material.
We quote each application in the unit that trade actually buys in, by the specimen or by the carat.
Durability and care
Hardness 5–5.5; cleavage imperfect {110}. That combination decides what it can safely be set into.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What hydroxylherderite costs
Indicative pricing for hydroxylherderite is Faceted stones $80–$400/ct; fine crystals $100–$5,000.
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 hydroxylherderite treated, and how?
Untreated. Most material sold as 'herderite' is the hydroxyl-dominant species; true fluorine-dominant herderite is rare. Strong blue fluorescence under shortwave UV is characteristic.
Where does hydroxylherderite come from?
Golconda and Linópolis, Minas Gerais, Brazil, Virgem da Lapa, Minas Gerais, Brazil, Mount Apatite, Auburn, Maine, USA and Erongo, Namibia. Origin affects price, so we name the locality rather than the country on every quote.
Is hydroxylherderite hard enough to wear every day?
Not really. At 5–5.5 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does hydroxylherderite cost?
Indicatively Faceted stones $80–$400/ct; fine crystals $100–$5,000. 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 hydroxylherderite confused with?
Most often Beryllonite, Apatite, Brazilianite and Phenakite. A refractive index of 1.592–1.621 and a specific gravity near 2.95–3.02 separate it quickly.
Related stones
Looking for hydroxylherderite?
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 hydroxylherderite