How Much Does a Ruby Cost?

Diamonds are bought according to a standardised scale: the four Cs provide a range that anyone can verify. Rubies have no equivalent scale. Their value is based first and foremost on a visual judgement — the intensity of the red — which no one has managed to standardise.

Four factors come into play, in order of real impact: colour, by far the most important; treatments, which can divide value by ten; dimensions, in millimetres rather than carats; and origin, which influences the price without ever determining it on its own.

A word of context before the figures. Ruby is a corundum, exactly like sapphire — the same formula, the same hardness of 9 out of 10, sometimes from the same deposit, with only the concentration of chromium setting them apart. But it is significantly rarer above two carats, and that is what explains the price gap between the two.

Six Mozambican rubies, recorded in September 2026. Prices including VAT, published online.

Six stones, Bonnot Paris stock, September 2026. Median: approximately €17,000/ct. Deliberately limited sample — we publish what we have, not a market benchmark.

To put these figures into perspective, two comparisons from our other surveys: the median for blue sapphire is around €1,780/ct for ring sizes, while that ofZambian emerald ranges from €3,200 to €6,100/ct depending on the bracket. Ruby therefore belongs in a category of its own — around nine times the price per carat of blue sapphire.

Read the last column of the table again: the price per carat falls as the weight rises. This is the opposite of what happens with almost all gemstones, where going from two to three carats costs far more than one third extra.

1.50 ct · €22,520/ct

The pure red

An intense red, without brown or pink, that remains clear as the light fades. The smallest stone in the selection, and by far the most expensive per carat. 33 780 €.

2.52 ct · €5,800/ct

The pinkish side

One carat more, a hue shifting towards pink — and a price per carat divided by nearly four. The same species, the same deposit. 14 610 €.

Here is what to take away from this article, if you remember only one thing: with ruby, half a carat less does not cost less if the colour is better. Weight is an adjustment variable; the saturation of the red is the price itself.

A very practical consequence when buying: be wary of a large ruby offered at a price that seems reasonable. Nine times out of ten, it is not a bargain — it is a more subdued colour, heavy treatment, or both.

Ruby geography shifted around fifteen years ago, and many buyers are still unaware of it.

Myanmar Myanmar retains its historical prestige — that of the stones from the Mogok Valley, and the commercial designation “pigeon’s blood” associated with them. These stones are rare on the market, and their sourcing is subject to constraints that complicate traceability.

Most of the fine gemstones available today come from Mozambique, particularly the Montepuez deposit. Our Mozambique rubies range from one and a half to two and a half carats, with certificates documenting their treatments.

As for price, the rule is the same as for all gem families: origin explains a character, never quality. Moreover, a laboratory only reaches a conclusion on origin when the inclusions allow it, and “origin undetermined” is not a flaw in the stone.

Ruby is the most treated and most imitated gemstone on the market. Two situations cause value to collapse, and neither can be seen with the naked eye.

Lead-glass filling. Stones so heavily fractured that they would be unsaleable are impregnated with a glass that fills the cracks and makes them visually presentable — often with a very flattering red colour. Their value bears no relation to that of a simply heated ruby, and they are unusually fragile: no ultrasound, heat or acidic products. A jeweller retipping a claw with a blowtorch can destroy the stone.

Synthesis. Ruby was the first gemstone to be industrially synthesised, from the beginning of the 20th^th century. Many antique jewels contain them, and do not always say so — not out of malice, but because it was common and accepted at the time.

By contrast, heatingdoes not diminish value: it is a traditional, stable and disclosed heat treatment, from which the vast majority of rubies on the market benefit. An unheated stone is worth more; a heated stone is in no way devalued. For the visual criteria and identifying features to look for, our guide to recognising a ruby details each case.

So far, we have discussed the stone alone. To this must be added the setting: from 1 250 € for a simple design to 10 000 € and more for extensive pavé or calibrated-stone work.

A ruby engagement ring therefore starts significantly higher than a sapphire ring, which starts at €2,500, or an emerald, at €1,700. This is not a pricing policy: it is the rarity of the raw material, as we see when purchasing in our sourcing markets.

If it is red that you are looking for rather than the word “ruby”, there is a serious answer — and it has six centuries of history behind it.

Red spinel is a distinct mineral species, long confused with ruby: several historic “rubies” in royal crowns have proved to be spinels. In our stock, its median is around €4,900/ct, compared with approximately €17,000/ct for ruby.

Its advantages are genuine. It is almost never treated — no oil, no glass, nothing to disclose or handle with care. Its hardness of 8 on the Mohs scale makes it suitable for everyday wear without reservation. And it is increasingly sought after in its own right, not as a substitute.

The caveat, plainly stated: it is not a ruby, and never will be. If it is the name, the history and the stone’s place in the hierarchy of gems that matter, no spinel will replace a red corundum. If you already own a red stone whose nature you do not know, our article on valuing your stone explains whom to contact to identify and have it appraised.