The facts
What phosphosiderite actually is
Mineralogically, phosphosiderite is iron phosphate — Fe³⁺PO₄·2H₂O, crystallising in the monoclinic system.
The colour is caused by fe³⁺ with hydration gives the peach-pink to reddish violet. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.692–1.739, and the specific gravity sits near 2.74–2.76; cleavage is good in one direction.
Where phosphosiderite comes from
The recognised sources are Sapucaia pegmatite, Minas Gerais, Brazil, Bull Moose Mine, Custer County, South Dakota, USA and Kreuzberg, Bavaria, Germany.
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 phosphosiderite is treated
Untreated but frequently resin-stabilised because the massive Chilean and Peruvian cabochon material is porous and friable. Soft enough that it should be kept out of rings.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What phosphosiderite is confused with
The usual confusions are Rhodochrosite, Charoite, Sugilite and Lepidolite.
The separation is rarely a matter of opinion: refractive index 1.692–1.739 and specific gravity 2.74–2.76 settle most of it in a minute, and magnification settles the rest.
What phosphosiderite is used for
Phosphosiderite is bought by jewellery and mineral collecting — 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 carat or by the specimen.
Durability and care
Phosphosiderite is 3.5–4 on the Mohs scale, with good in one direction cleavage.
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 phosphosiderite costs
Indicative pricing for phosphosiderite is Cabochons 10–60 USD; fine crystals 50–400 USD.
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 phosphosiderite treated, and how?
Untreated but frequently resin-stabilised because the massive Chilean and Peruvian cabochon material is porous and friable. Soft enough that it should be kept out of rings.
Where does phosphosiderite come from?
Sapucaia pegmatite, Minas Gerais, Brazil, Bull Moose Mine, Custer County, South Dakota, USA and Kreuzberg, Bavaria, Germany. Origin affects price, so we name the locality rather than the country on every quote.
Is phosphosiderite hard enough to wear every day?
Not really. At 3.5–4 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 phosphosiderite cost?
Indicatively Cabochons 10–60 USD; fine crystals 50–400 USD. 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 phosphosiderite confused with?
Most often Rhodochrosite, Charoite, Sugilite and Lepidolite. A refractive index of 1.692–1.739 and a specific gravity near 2.74–2.76 separate it quickly.
Related stones
Looking for phosphosiderite?
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 phosphosiderite