The facts
What ruby actually is
The species behind ruby is corundum, Al₂O₃; it forms in the trigonal system.
Chromium 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 1.762–1.770 and a specific gravity of about 3.97–4.05, with none; parting along twin planes cleavage.
Where ruby comes from
Commercial material comes from Mogok and Mong Hsu, Myanmar, Montepuez, Mozambique, Winza, Tanzania, Luc Yen, Vietnam and Chanthaburi trade, Thailand.
Different localities give different colour and different clarity, and the trade prices them differently. We state which one.
How ruby is treated
Heat is the norm. Lead-glass filling is common in cheap goods and must be disclosed — it is a composite, not a treated stone.
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 ruby is confused with
Watch for Red spinel, Rubellite, Garnet and Lead-glass composite — these are what turn up sold under this name.
The separation is rarely a matter of opinion: refractive index 1.762–1.770 and specific gravity 3.97–4.05 settle most of it in a minute, and magnification settles the rest.
What ruby is used for
The trades that buy ruby are jewellery, watch dials, mineral collecting and technical and precision components. 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 carat, by the disc or by the specimen.
Durability and care
Ruby is 9 on the Mohs scale, with none; parting along twin planes 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 ruby costs
Expect roughly $100–100,000/ct, 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.
Questions
Is ruby treated, and how?
Heat is the norm. Lead-glass filling is common in cheap goods and must be disclosed — it is a composite, not a treated stone.
Where does ruby come from?
Mogok and Mong Hsu, Myanmar, Montepuez, Mozambique, Winza, Tanzania, Luc Yen, Vietnam and Chanthaburi trade, Thailand. Origin affects price, so we name the locality rather than the country on every quote.
Is ruby hard enough to wear every day?
Yes. At 9 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 ruby cost?
Indicatively $100–100,000/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 ruby confused with?
Most often Red spinel, Rubellite, Garnet and Lead-glass composite. A refractive index of 1.762–1.770 and a specific gravity near 3.97–4.05 separate it quickly.
What is ruby used for besides jewellery?
watch dials, mineral collecting and technical and precision components. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for ruby?
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 ruby