Sapphire & spinel
Sapphire from Sri Lanka, Madagascar and East Africa, in blue and in every fancy colour; and spinel, the stone most often mistaken for ruby, from Tanzania and Sri Lanka.
Origins
Where fine stones come from
A short guide to the principal sources of emerald, ruby and tourmaline: how each one forms, what it leaves in the finished stone, and what a laboratory can tell you about it.
Geography
Why origin moves the price
Emerald, ruby and tourmaline each form in only a few kinds of rock, and those rocks occur in only a few places. The chemistry of the host rock — how much iron, chromium, vanadium or copper was there when the crystal grew — sets the colour, and the conditions of growth set the inclusions.
That is why origin is more than romance. Two emeralds of the same weight and the same green can carry very different prices because one is Colombian and the other is not, and a laboratory can usually tell them apart from the inclusions alone.
It is also why an origin should be stated carefully. A laboratory’s origin determination is an expert opinion rather than a measurement, and good laboratories occasionally disagree. Every invoice of ours says what an origin rests on.
Map shown for orientation only; not to scale.
01 — Colombia
Colombian emerald
The benchmark for emerald, and the origin every other is measured against.
Colombian emerald grows in black shale and limestone in the Eastern Cordillera, in veins left by hot brines that never met a granite — a geology found almost nowhere else. The colour is a warm, pure green with a soft, velvety glow, and the classic deposits of Muzo, Coscuez and Chivor have been worked for centuries.
Almost all Colombian emerald is oiled, and has been for as long as it has been traded. An eye-clean Colombian stone that has never been oiled is among the scarcest things in coloured stones, and its price says so.
- Species
- Beryl, var. emerald
- Colour
- Warm, pure green
- Deposit
- Hydrothermal vein, shale-hosted
- Usual treatment
- Oil, very commonly
- Known for
- Warmth and glow of colour
02 — Zambia
Zambian emerald
Cooler, bluer and often cleaner than Colombian — and today the largest source of fine emerald by volume.
Zambian emerald formed where fluids carrying beryllium met chromium-rich schist, near Kitwe in the north of the country. Iron in the crystal gives the green a slightly bluish, sometimes darker cast, quite distinct from the warmer Colombian material, and the stones tend to be less included at a given size.
Zambia produces in volume and at size, which makes it the natural origin for matched calibrated goods and for larger clean stones at a sensible price. Fine Zambian emerald is increasingly bought on its own merits rather than as an alternative to Colombia.
- Species
- Beryl, var. emerald
- Colour
- Cool, slightly bluish green
- Deposit
- Schist-hosted
- Usual treatment
- Oil, often lightly
- Known for
- Clarity and size
03 — Brazil
Brazilian tourmaline
The great tourmaline country, and the home of the copper-bearing Paraíba material that changed the market.
The pegmatites of Minas Gerais have given tourmaline in every colour the species takes — indicolite blues, verdelite greens, rubellite, bicolour and watermelon — for well over a century, and they still do. Brazil produces emerald too, from Bahia and Minas Gerais, mostly in commercial qualities.
In the late 1980s a small deposit in the state of Paraíba gave up tourmaline coloured by copper: a neon blue-green that nothing else in the species approaches. The trade and the laboratories now use the name for copper-bearing tourmaline of the same chemistry from Nigeria and Mozambique as well.
- Species
- Tourmaline (elbaite)
- Varieties
- Indicolite, verdelite, rubellite, bicolour, Paraíba
- Deposit
- Granitic pegmatite
- Usual treatment
- Heat, for some colours
- Note
- Paraíba-type is copper-bearing
04 — Mozambique
Mozambique ruby
The deposit that reshaped the ruby market after its discovery in 2009.
Mozambique ruby comes from amphibolite in Cabo Delgado, in the north of the country. Its iron content sits between the marble-type rubies of south-east Asia and the dark, iron-rich stones of the old basalt deposits, which gives a bright red with good fluorescence — and a share of the material is fine enough to need no heat at all.
Ruby is corundum, not beryl — considerably denser than emerald. A ruby and an emerald of identical weight are visibly different sizes, which catches out buyers working from carat figures alone. Our size tool in the Studio shows the difference at true scale.
- Species
- Corundum, var. ruby
- Colour
- Pink through to full red
- Deposit
- Amphibolite-hosted, metamorphic
- Usual treatment
- Heat, very commonly
- Specific gravity
- 4.00 — denser than beryl
05 — Nigeria
Nigerian tourmaline
Rubellite of a rare depth, and some of the finest Paraíba-type material outside Brazil.
Nigeria’s tourmaline comes from pegmatites across the centre and south-west of the country, worked largely by hand. It is best known for rubellite: a deep raspberry to purplish red that holds its colour under incandescent light, which is the test most rubellite fails.
Since the early 2000s Nigeria has also given copper-bearing tourmaline in the Paraíba colours, often in larger and cleaner pieces than the Brazilian original, along with blues and greens across the range.
- Species
- Tourmaline (elbaite)
- Varieties
- Rubellite, Paraíba-type, blue and green
- Deposit
- Granitic pegmatite
- Usual treatment
- Heat, for some colours
- Best sizes
- 5 ct and above
Beyond the three
Other stones, through the same trade
Emerald, ruby and tourmaline are what we hold in depth. They are not the limit of what we can put in front of you.
Aquamarine & morganite
The other colours of beryl — aquamarine, morganite and heliodor — from Brazil, Madagascar and Nigeria, in sizes few other species reach.
Tanzanite & garnet
Tanzanite from the single deposit near Mount Kilimanjaro that produces it, and garnet in every colour, including tsavorite and spessartite from East Africa.
If you need volume in something outside our core three, tell us. We know who deals in what, and we would rather say plainly whether we can find it than take an order we cannot fill.
Responsibility
Buying carefully, in a trade that needs it
The coloured-stone trade does not have a spotless record, and a house that buys through it inherits some of that. What we can set out is how we work.
One standard for every parcel
Every parcel is checked the same way, whoever offers it: what it is, where it is said to come from, and whether the paperwork that comes with it holds together. Material that fails any of those is declined.
Known counterparties
We buy from people we know and have worked with over years. We do not buy anonymous parcels of unknown origin, we screen the parties we deal with against the applicable sanctions lists, and we decline material we cannot account for — which happens more often than you might expect.
Correct export
Goods enter and leave the United Arab Emirates under proper declaration and enter their destination market under that market’s rules. Customs and compliance documentation is issued as standard rather than on request.
Honest description
Origin and clarity are stated as they are, and treatment is a single word: none. Where we are uncertain about something — and origin determination is opinion, not measurement — we tell you that too.
Independent checking
We are happy to be checked. Stones can be sent to a laboratory of your choosing before payment clears, and established trade clients can view on memo.
Long relationships
This trade runs on repeat business. A house that misrepresents a stone gets one sale; a house that describes it accurately gets twenty years. We have chosen the second.
Enquiries
Looking for a particular origin?
Tell us the origin, colour and size you work with, and we will tell you honestly what we can supply, what is scarce, and what will take time to find.