Ruby$11,800+1.4%Sapphire$86,000-0.4%Sapphire$11,500+1.8%Emerald$34,000+1.3%Emerald$13,200+2.6%Paraíba Tourmaline$42,000+4.7%Paraíba Tourmaline$13,000+3.1%Spinel$6,200+0.6%Cobalt Spinel$21,000+5.2%
WORLDWIDE LAUNCHFebruary 2027
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Home / MARKET GUIDE

Market Guide

What decides the value of a coloured stone, the reference prices, and the story of each stone.

01 / WHAT SETS THEM APART

What sets them apart

Two stones can look alike across a room and differ in value by a multiple. Four things decide where any coloured stone falls: the four C’s, where it formed, whether its mine still produces, and whether anything was done to it.

THE FOUR C’S

Colour leads

Colour, clarity, cut and carat are the traditional four, but in coloured stones they do not weigh the same. Colour dominates: hue, saturation and tone together move a price further than anything else. Clarity is judged by species, not by diamond standards. Cut is often a compromise between keeping weight and returning light, and price per carat climbs steeply with size.

ORIGIN AND GEOLOGY

Where it formed

Every stone grew under its own heat, pressure and chemistry. Trace elements decide the colour: chromium for the red of ruby and the green of fine emerald, iron and titanium for the blue of sapphire, copper for the neon of Paraíba, vanadium for tsavorite. Those conditions leave a fingerprint of inclusions and chemistry that top laboratories read to name a stone’s origin, and origin alone can multiply a price.

DEPLETING MINES

Supply that cannot grow

Some of the deposits that define their species no longer produce. Kashmir sapphire came out of the ground in a few years in the 1880s. The original Paraíba workings in Brazil are largely exhausted, and fine material from Muzo’s best pockets appears rarely. When a source closes, the stones already mined are all there will ever be.

TREATMENT

The dividing line

Most coloured stones in trade have been heated, oiled or filled to improve how they look. Certified untreated stones are the rare top tier and trade at a multiple of treated ones. That is why Vault Trade admits untreated stones only, and why Stock Trade states every enhancement on every listing.

The four C’s, and what moves the price further

In coloured stones the four do not carry equal weight: colour dominates, and origin and treatment can move a price by a multiple rather than a percentage.

COLOUR
The dominant driver
Hue, saturation and tone together account for more of a fine stone’s price than any other factor. The step from good to fine colour can triple the per-carat figure.
CLARITY
Judged by species
Eye-clean is expected in blue sapphire. In emerald, inclusions are normal and graded against the species, not against diamond standards.
CUT
Weight against light
Coloured stones are often cut to keep weight rather than to return light. A well-proportioned stone without a window commands a clear premium over a native cut of the same weight, which is why fine stones are often recut.
CARAT
Non-linear
Price per carat accelerates with size. Fine untreated stones become dramatically scarcer above 3 carats, and the market prices that scarcity directly.
ORIGIN
A multiplier, not a label
The same stone with a Kashmir origin report can be worth several times its origin-undetermined price. Within ruby, a Montepuez origin report commands a clear premium over origin-undetermined material of equal grade.
TREATMENT
The dividing line
Roughly 95% of ruby and sapphire in trade is heat treated, and virtually all emerald is oiled. Certified untreated stones trade at two to five times heated equivalents.
CERTIFICATION
Where value is proven
GRS, SSEF, Gübelin and AGL reports establish species, treatment and origin. On stones where those findings carry the price, the report is part of the asset.
02 / PRICE INDEX

Where prices sit, and what sets them

STONE2-3 CT3-5 CT5-10 CTCHG30D
Ruby, no heat
Montepuez, Mozambique
 $7,500$11,800$18,400 +1.4% View all
Sapphire, no heat
Kashmir
 $58,000$86,000$135,000 -0.4% View all
Sapphire, no heat
Sri Lanka
 $6,800$11,500$19,800 +1.8% View all
Emerald, no oil
Muzo, Colombia
 $22,000$34,000$52,000 +1.3% View all
Emerald, no oil
Kagem, Zambia
 $8,600$13,200$19,500 +2.6% View all
Paraíba Tourmaline
Paraíba, Brazil
 $28,000$42,000$60,000 +4.7% View all
Paraíba Tourmaline
Mozambique
 $8,500$13,000$18,000 +3.1% View all
Spinel, no heat
Mahenge, Tanzania
 $3,800$6,200$9,800 +0.6% View all
Cobalt Spinel
Luc Yen, Vietnam
 $14,200$21,000— +5.2% View all
Indicative mid-market reference for fine-quality untreated material, compiled from published 2026 trade price guides and auction results. Ranges in this market are extremely wide: fine unheated ruby of top colour is quoted anywhere from $15,000 to over $100,000 per carat, and Kashmir sapphire from $50,000 to beyond $200,000, depending on colour, clarity and certification. These figures describe the middle of the fine-grade band and are a reference to check a listing against, not a quotation. CGEMX will publish its own index from cleared trades once volume supports it.
03 / PERFORMANCE

Why precious stones hold value

Ruby Sapphire Emerald
ILLUSTRATIVE INDEX · BASE 100
100200300 400500 0510 1520
5Y
+31 / +47%
10Y
+71 / +116%
15Y
+124 / +217%
20Y
+194 / +366%

Illustrative index modelled on published trade estimates of 4–8% average annual appreciation. Not a forecast, and not investment advice.

04 / READING THE INDEX

What these numbers are, and what they are not

A REFERENCE

Mid-market, per carat

Each figure is an indicative mid-market price per carat for fine material of that species and origin, in that carat band, with no treatment and a top-tier origin report. It is a point to measure a specific stone against, not a quotation for any stone.

NOT A QUOTATION

Individual stones vary widely

Two stones of identical weight and origin can differ by a multiple. Colour saturation, the presence or absence of a window, the cutting, and clarity all move a price far further than the carat band alone suggests.

WHERE IT COMES FROM

Published trade sources

Compiled from published price guides, auction results and dealer surveys. As volume on the exchange builds, CGEMX will publish its own index from cleared trades, which is the only genuinely reliable basis for a reference price.

05 / THE STONES

Every stone, its story

Five are on CGEMX today. The others list when real stones arrive, never before.

ON CGEMX

Ruby

The rarest of the great coloured stones

ON CGEMX

Sapphire

Kashmir closed a century ago; fine colour stays scarce

ON CGEMX

Emerald

Oil-free emerald is the true rarity

ON CGEMX

Paraíba Tourmaline

Discovered in 1987, and already scarce

ON CGEMX

Spinel

The connoisseur’s stone, still undervalued

GUIDE

Tsavorite

A garnet the colour of fine emerald

GUIDE

Demantoid

The garnet with more fire than diamond

GUIDE

Rubellite

Tourmaline that stays red

GUIDE

Alexandrite

Green by day, red by night

GUIDE

Padparadscha

The lotus sapphire

GUIDE

Tanzanite

One source on Earth

GUIDE

Aquamarine

The blue of sea water

GUIDE

Morganite

Pink beryl, named for a collector

GUIDE

Imperial Topaz

Topaz in its rarest colours

FOR MEMBERS

Measure a stone against the index before you buy

Every listing on the exchange shows its price per carat alongside the asking price. Signed in, your holdings are plotted against these benchmarks directly, so you can see at a glance which of your stones sit above the reference and which sit below.