The facts
What lava rock actually is
Mineralogically, lava rock is vesicular volcanic rock — Silicate glass and minerals, crystallising in the amorphous system.
The colour is caused by iron oxides. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer gives nothing, because the material is opaque, and the specific gravity sits near 0.6–1.5; cleavage is none.
Where lava rock comes from
The recognised sources are Indonesia, Iceland, Italy and Kenya.
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.
Is lava rock treated?
None. Dyed versions exist for aquaria.
Nothing needs disclosing, and nothing about the stone can change after you buy it. If a price looks impossible, the risk is substitution rather than treatment.
What lava rock is confused with
The usual confusions are Pumice, Scoria and Ceramic imitations.
Because the material is opaque, refractive index is no help. Specific gravity around 0.6–1.5, hardness of 5–6, streak and magnification do the work instead.
What lava rock is used for
Lava rock is bought by aquascaping, landscaping, jewellery, sauna stones and filtration — 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 kilo, by the tonne or by the carat.
Durability and care
Lava rock is 5–6 on the Mohs scale, with none 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 lava rock costs
Indicative pricing for lava rock is $0.20–3/kg.
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 lava rock treated?
None. Dyed versions exist for aquaria.
Where does lava rock come from?
Indonesia, Iceland, Italy and Kenya. Origin affects price, so we name the locality rather than the country on every quote.
Is lava rock hard enough to wear every day?
Not really. At 5–6 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 lava rock cost?
Indicatively $0.20–3/kg. 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 lava rock confused with?
Most often Pumice, Scoria and Ceramic imitations. Since the material is opaque, separation relies on specific gravity near 0.6–1.5, hardness and magnification.
What is lava rock used for besides jewellery?
aquascaping, landscaping, sauna stones and filtration. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for lava rock?
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 lava rock