The facts
What astrophyllite actually is
Mineralogically, astrophyllite is astrophyllite — (K,Na)₃(Fe²⁺,Mn)₇Ti₂Si₈O₂₄(O,OH)₇, crystallising in the triclinic system.
The colour is caused by bronze to golden-yellow from Fe²⁺ with Mn in the octahedral sheet; an Fe–Ti charge-transfer contribution is plausible but not confirmed for this species. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.678–1.758, and the specific gravity sits near 3.20–3.40; cleavage is perfect {001}, poor {100} — micaceous, which is what limits it to cabochons and slabs.
Where astrophyllite comes from
The recognised sources are Låven Island, Langesundsfjord, Norway (type locality), Khibiny and Lovozero massifs, Kola Peninsula, Russia, St Peters Dome, El Paso County, Colorado, USA and Mont Saint-Hilaire, Quebec, Canada.
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 astrophyllite is treated
Untreated, often resin-stabilised because the bladed aggregate is fragile. Cut for the golden radiating star-like sprays against dark feldspar and aegirine matrix. Strongly pleochroic from deep orange-red through orange-yellow to lemon. Far too soft for rings.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What astrophyllite is confused with
The usual confusions are Nuummite, Seraphinite, Bronzite, Golden mica and Pyrite in matrix.
The separation is rarely a matter of opinion: refractive index 1.678–1.758 and specific gravity 3.20–3.40 settle most of it in a minute, and magnification settles the rest.
What astrophyllite is used for
Astrophyllite is bought by carving and sculpture, decorative objects, mineral collecting, jewellery and wellness and body care — 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 block, by the piece or by the specimen.
Durability and care
Astrophyllite is 3–4 on the Mohs scale, with perfect {001}, poor {100} — micaceous, which is what limits it to cabochons and slabs 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 astrophyllite costs
Indicative pricing for astrophyllite is $1–25/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 astrophyllite treated, and how?
Untreated, often resin-stabilised because the bladed aggregate is fragile. Cut for the golden radiating star-like sprays against dark feldspar and aegirine matrix. Strongly pleochroic from deep orange-red through orange-yellow to lemon. Far too soft for rings.
Where does astrophyllite come from?
Låven Island, Langesundsfjord, Norway (type locality), Khibiny and Lovozero massifs, Kola Peninsula, Russia, St Peters Dome, El Paso County, Colorado, USA and Mont Saint-Hilaire, Quebec, Canada. Origin affects price, so we name the locality rather than the country on every quote.
Is astrophyllite hard enough to wear every day?
Not really. At 3–4 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 astrophyllite cost?
Indicatively $1–25/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 astrophyllite confused with?
Most often Nuummite, Seraphinite, Bronzite, Golden mica and Pyrite in matrix. A refractive index of 1.678–1.758 and a specific gravity near 3.20–3.40 separate it quickly.
What is astrophyllite used for besides jewellery?
carving and sculpture, decorative objects, mineral collecting and wellness and body care. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for astrophyllite?
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 astrophyllite