Gemstones
Eight colored stones come up again and again in serious buying. Here is what each one is, what moves its price and how rare fine examples are, with links to the ones on the shop.
IllustrationThe eight stones
There is no price list for colored stones, as there is for gold: color, treatment, origin, size and the lab report decide where a stone sits in its range.
Red corundum, colored by chromium: the same mineral as sapphire. The finest are a pure, glowing red. Most rubies are heated to improve color and clarity, which the trade accepts.
Corundum in every color except red. Blue is the classic; pink, yellow, purple, padparadscha and color-change sapphires each have a market of their own.
A mineral of its own, mistaken for ruby for centuries. Red, hot pink, cobalt blue, purple and gray, and most of it sold untreated.
Green beryl, colored by chromium and vanadium. Inclusions are normal, and nearly every emerald is filled with oil or resin to make fractures less visible.
Tourmaline colored by copper, found in Brazil's Paraíba state in the late 1980s and later in Nigeria and Mozambique. Its neon blue to green has no close rival.
A variety of chrysoberyl that changes color: green or bluish green in daylight, red or purplish red under incandescent light.
Green grossular garnet from East Africa, from Kenya and Tanzania, found in the late 1960s. Bright, lively and usually untreated.
Hydrated silica. Precious opal shows play-of-color, flashes of spectral color that move as the stone turns. The main types are black, boulder, white, crystal and fire opal.
Under ultraviolet light
Under ultraviolet light some stones glow. Reports often note it, and for a few stones it matters to price.
Chromium makes rubies and red spinels fluoresce red, and in daylight that glow adds to the color, which is one reason Burmese rubies are prized. Iron suppresses it, so iron-rich rubies, like many from the Thai–Cambodian border, look darker and barely fluoresce.
In sapphire and emerald, a laboratory reads fluorescence as one clue among many: a chalky glow under short-wave ultraviolet can point to heating in some sapphires, and some fillers in emeralds fluoresce. Paraíba tourmaline is usually inert, while many opals glow white or bluish. Fluorescence is a clue, not a verdict: a report weighs it with everything else.
Natural or not
Six of the eight stones on this page (all but Paraíba tourmaline and tsavorite, which are imitated by glass and other materials instead) are also grown in laboratories, sometimes with the same chemistry as the natural one, and sell for a fraction of the price. Treatments such as heat, diffusion and fillers move value just as much. Telling them apart takes a gemological laboratory.
A report from a recognized lab states natural or lab-grown, the treatment and, on request, the origin. Check it on the lab's own website, and remember what a lookup proves: that the report exists, not that it describes the stone in front of you. The report describes a stone; the passport proves it's this one.
Next
Buying: every lot states how far it has been checked, and the money is held, so no seller is paid before the stone has been checked against its description. Selling: list the stone from your cabinet (a private owner pays a one-time $20 listing fee, and the desk confirms the payment and reviews the lot before it goes live), then sell safely through Everystone with no commission under $10k while we launch and 5% from $10k. Holding: from $30k, a free-zone vault in Bangkok, insured at documented value, for 3.5% a year.
Among these eight, the hardest to find in fine quality are Paraíba tourmaline from Brazil, alexandrite with a strong color change, and unheated ruby above a few carats. Rarity is always about quality: commercial grades of every stone here are easy to buy.
It describes how the stone glows under ultraviolet light. In rubies and red spinels, strong red fluorescence comes with chromium and adds to the color in daylight; in sapphire and emerald, labs read it as one clue among many about heating or fillers. It is rarely the deciding factor on its own.
No. Lab-grown ruby, sapphire, spinel, emerald, alexandrite and opal can look the same as natural stones, and some have the same chemistry, but they sell for a small fraction of comparable natural stones. A report from a recognized lab states which it is.
Buy where the money is held until you have the stone, the lot states what has been checked, and the report can be looked up at the lab. On Everystone, every lot shows its verification level and every purchase is a protected payment.
Every lot shows how far it has been checked, and every purchase is a protected payment. Browsing needs no account.
