We buy blue sapphire rough.

Frequently milky, silky or colour-zoned in rough. Dry material reads grey — the difference between wet and dry on blue sapphire rough is larger than on almost anything else.

How to tell if this is what you have

What it gets mistaken for

Blue sapphire is commonly confused with iolite, tanzanite, spinel, benitoite and synthetic corundum. That cuts both ways — people sell it as something less than it is at least as often as the reverse. If you are not certain what you have, send photographs anyway and say you are not sure. We would far rather look at something and tell you it is not what you hoped than have you throw it back on the heap.

Also traded as: corundum.

Where it comes from

We buy blue sapphire from Sri Lanka, Madagascar, Australia, Tanzania, Nigeria, Thailand, China, United States — and from anywhere else it turns up. A locality we have not listed is an omission, not a refusal.

Treatment

Heating routine and expected. Diffusion and beryllium treatment excluded.

Tell us what has been done to it, if you know. We buy treated material where the treatment is a normal part of the trade — what we cannot do is find out afterwards, because then it is a problem for whoever owns the stone next and eventually that is us.

How to photograph it

Daylight, on a plain white surface, and wet and dry both. Rough seen dry is frosted and reads far paler and greyer than the same stone wet — a parcel photographed dry has cost its owner money more times than we can count. Put a coin or a ruler in the frame for scale. The full guide is here.

← every stone we buy