There is no single answer to "how much is a ruby per carat", because weight is only one of the things being priced. There is, however, a short list of reasons that explains almost every ruby price. Here it is, shown on rubies we hold now, with prices in Kuwaiti dinars exactly as they appear on each stone's page.
How much is a ruby per carat?
Across our rubies today, the price per carat runs from about 75 KWD to about 680 KWD. The reasons a stone sits where it does follow, roughly in the order they matter.
When is a red stone called ruby?
Ruby and sapphire are the same mineral, corundum. The name ruby is kept for red of real strength. Corundum that is paler or pinker than that is traded as pink or red sapphire. We apply the stricter standard: a stone is called ruby on this site when its colour earns the name.
Which red costs the most?
Colour is the largest single factor in a ruby's price. The finest ruby is a pure, vibrant red to slightly purplish red, strong without being too dark. As the colour moves clearly towards orange or towards purple, the price moves a step down.
Our three vivid pinkish red rubies from Mozambique show how consistent this is when the variables are held still. The Vivid Pinkish Red Ruby · 1.02 ct is 380 KWD, the Vivid Pinkish Red Ruby · 1.20 ct is 450 KWD, and the Vivid Pinkish Red Ruby · 1.27 ct is 475 KWD. All three are untreated, and all three come to about 373 to 375 KWD per carat: the same colour, the same size band and the same treatment state give almost the same price.
Colour also explains why a large ruby can cost less per carat than a small one. Our Purplish Red Ruby · 7.98 ct, untreated, from Afghanistan, is 600 KWD, about 75 per carat. It is a stone for someone who likes a deep, cool red and wants a size few rubies reach.
Heated or untreated: how much does it change?
Heat is the standard treatment for ruby. It improves colour and clarity, and the result is permanent. A ruby that needed no treatment is rarer, and it is priced above a heated stone of the same colour and size. Our product pages state the laboratory's finding in fixed terms:
- Untreated — the laboratory found no treatment.
- No indication of heat — heat has been ruled out; the report makes no wider statement.
- Treated - Heat — the laboratory found evidence of heating.
- Not determined — the stone has a report, but it does not settle treatment.
- Untested — no report exists, so treatment was not examined.
Heated rubies are the most accessible way into the species. Our Siam Ruby · 0.50 ct, heated, is 120 KWD, about 240 per carat. Our Pinkish-Red Ruby · 2.30 ct, a cabochon from Afghanistan, carries No indication of heat and is 333 KWD.
Does origin matter?
It can. Burma, and the Mogok valley in particular, was historically the source of the finest rubies, and a Burmese origin still carries weight in the trade. Today some of the world's finest rubies come from Mozambique, Madagascar and Zambia. "Siam" is the trade's name for ruby from Thailand, and Greenland has recently joined the list of sources. Origin appears on the report when the laboratory can determine it.
How much does size add?
Fine-quality ruby over one carat is very rare, so the price per carat itself rises with size, not only the total. The rise is steepest in the best colours. A two-carat ruby of a given quality is usually priced at considerably more than twice a one-carat stone of the same quality.
Do inclusions and cut matter?
Ruby without any inclusions practically does not exist, and the trade expects some. What moves the price is where they sit and how many there are: inclusions visible under the table, the large top facet, take from the brightness and lower the value. Ovals and cushions are the most common shapes because they suit the shape of the rough crystal. A well-judged cut keeps the colour across the whole stone; a shallow one leaves a "window" in the centre where light passes straight through.
What should the laboratory report say?
For any ruby at a serious price, the report confirms that the stone is natural corundum of the ruby variety, states its treatment and, where possible, its origin. On every certified stone we sell, those findings are transcribed into the specification on the product page, together with the report number.
Rubies are best judged in daylight and side by side. Viewings are by appointment in Kuwait City: book a private viewing, or see all our rubies.