Olivine (Foundry and Industrial)

What olivine (Foundry and Industrial) actually is

The species behind olivine (Foundry and Industrial) is crushed dunite - a near-monomineralic olivine rock - used as foundry moulding sand, slag conditioner and refractory, and increasingly for carbon mineralisation, Forsterite-rich olivine (Mg,Fe)2SiO4, typically Fo90-93; it forms in the orthorhombic (supplied as crushed sand) system.

Olive to bottle green from Fe2+; serpentinised material is duller is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.

On the instruments it reads a refractive index of 1.64-1.69 and a specific gravity of about 3.20-3.40, with poor; conchoidal fracture cleavage.

Where olivine (Foundry and Industrial) comes from

Commercial material comes from Aheim and Gusdal, Møre og Romsdal, Norway - the world's largest dunite operation, Åheim and Raudbergvik, Norway, Washington State and North Carolina, USA and Turkiye, Spain and Japan.

Different localities give different colour and different clarity, and the trade prices them differently. We state which one.

How olivine (Foundry and Industrial) is treated

Crushed, dried and graded; not chemically treated. Chosen as a foundry sand specifically because it contains no free silica, so it avoids the silicosis risk of silica sand, and because it resists metal penetration in manganese steel casting. Also used for blast-furnace slag conditioning, refractory ramming mixes, and as blasting grit. FAST-GROWING NEW USE: olivine weathers rapidly and captures CO2, so it is central to several enhanced rock weathering carbon-removal ventures - a genuinely expanding market. Serpentinised dunite can contain chrysotile, so asbestos screening matters.

We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.

What olivine (Foundry and Industrial) is confused with

Watch for Silica sand (cheaper, but a silicosis hazard), Chromite foundry sand, Zircon sand and Peridot (the gem variety of the same mineral) — these are what turn up sold under this name.

The separation is rarely a matter of opinion: refractive index 1.64-1.69 and specific gravity 3.20-3.40 settle most of it in a minute, and magnification settles the rest.

What olivine (Foundry and Industrial) is used for

The trades that buy olivine (Foundry and Industrial) are heavy industry and abrasives. They do not want the same thing, and they do not pay in the same unit.

We quote each application in the unit that trade actually buys in, by the tonne.

Durability and care

Hardness 6.5-7; cleavage poor; conchoidal fracture. That combination decides what it can safely be set into.

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 olivine (Foundry and Industrial) costs

Expect roughly $60-200 per tonne depending on grade and freight, depending on quality.

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.

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