The facts
What macusanite actually is
Mineralogically, macusanite is peraluminous rhyolitic volcanic glass — Silicate glass rich in Li, B and F, crystallising in the amorphous system.
The colour is caused by trace Fe gives a pale olive to yellow-green; the material is unusually transparent for a volcanic glass. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.483–1.492, and the specific gravity sits near 2.34–2.38; cleavage is none; conchoidal fracture.
Where macusanite comes from
The recognised sources are Macusani, Carabaya Province, Puno, Peru.
That is the whole list. A single source makes supply fragile and makes any claim of a second origin worth questioning.
How macusanite is treated
Untreated. Often mislabelled as a tektite, which it is not — it is a terrestrial volcanic glass, though its low iron and high transparency make it look tektite-like. It is also the source of much lithium-boron research material.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What macusanite is confused with
The usual confusions are Moldavite, Libyan desert glass, Obsidian and Green glass.
The separation is rarely a matter of opinion: refractive index 1.483–1.492 and specific gravity 2.34–2.38 settle most of it in a minute, and magnification settles the rest.
What macusanite is used for
Macusanite 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
Macusanite is 5.5–6 on the Mohs scale, with none; conchoidal fracture 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 macusanite costs
Indicative pricing for macusanite is Rough 1–10 USD per gram; faceted stones 10–60 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 macusanite treated, and how?
Untreated. Often mislabelled as a tektite, which it is not — it is a terrestrial volcanic glass, though its low iron and high transparency make it look tektite-like. It is also the source of much lithium-boron research material.
Where does macusanite come from?
Macusani, Carabaya Province, Puno, Peru. That is the only commercial source.
Is macusanite hard enough to wear every day?
Yes. At 5.5–6 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 macusanite cost?
Indicatively Rough 1–10 USD per gram; faceted stones 10–60 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 macusanite confused with?
Most often Moldavite, Libyan desert glass, Obsidian and Green glass. A refractive index of 1.483–1.492 and a specific gravity near 2.34–2.38 separate it quickly.
Related stones
Looking for macusanite?
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 macusanite