Why Does Turquoise Look So Different?
Sky blue, deep green, veined, clean. A guide to turquoise varieties and what actually causes the difference.
Hold two pieces of turquoise side by side and they can look like entirely different stones. One might be a clean, uniform robin's egg blue. The other a mottled green, shot through with a web of dark brown lines. Both are genuinely turquoise. The difference comes down to exact chemistry, where in the world the stone formed, and what else happened to be sitting in the rock around it at the time.
This is a look at what turquoise actually is, why its colour shifts from blue to green, what that veining running through it is, and the main varieties you're likely to come across, including the one we stock.
What Turquoise Actually Is
Turquoise is a hydrated phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It forms in arid and semi-arid regions, typically near the surface, where acidic groundwater slowly percolates through rock containing both copper and aluminium-rich minerals, depositing turquoise in the cracks and cavities it leaves behind.
This is why turquoise deposits are so often found close to copper mines. The same copper-bearing rock that makes an area worth mining for metal is exactly the environment turquoise needs to form in the first place. Significant deposits cluster in the American Southwest, Iran, China and the Sinai Peninsula, largely because those regions share the right combination of arid climate and copper-rich geology.
Why the Colour Changes: Copper vs Iron
Turquoise's colour comes down to a fairly simple chemical trade-off. Copper is what gives turquoise its blue. The more copper relative to other elements in a given sample, the closer it sits to that classic, pure sky blue.
Iron is the main culprit behind the shift toward green. When iron substitutes for some of the aluminium in the mineral's structure, it pulls the colour away from blue and toward green, sometimes all the way to a yellowish, olive-green. Zinc can also substitute into the structure in smaller amounts and is associated with a brighter, slightly paler blue in certain deposits.
So two pieces of turquoise can be chemically almost identical, both genuinely CuAl6(PO4)4(OH)8·4H2O, and still look nothing alike, simply because one formed with a higher iron content than the other. Colour in turquoise isn't a grading flaw or a sign of lower quality. It's a direct record of the exact geochemistry of the spot it formed in.
What the Veining Actually Is: Matrix
The brown, black or golden webbing you sometimes see running through turquoise is called matrix, and it isn't a flaw either. It's the host rock itself, the material the turquoise formed within, left behind as thin veins where the turquoise didn't fully replace the surrounding stone.
Dark matrix usually comes from iron oxides or manganese oxides staining the host rock. Brown, chocolate-toned matrix is typically iron oxide specifically. Lighter, golden or honey-coloured matrix often comes from the rhyolite or limestone the turquoise formed inside. Some matrix patterns are prized in their own right, the tight, spiderweb-like matrix associated with certain Nevada mines being a well-known example that collectors specifically look for rather than avoid.
Turquoise with no matrix at all, a clean, uniform colour straight through, tends to come from deposits where the host rock was especially pure, with Persian turquoise being the best-known example of this clean, matrix-free look.
Major Turquoise Varieties
Mined in Iran for well over five thousand years, Persian turquoise set the standard most people still picture when they think of the stone: a clean, uniform, slightly intense sky blue with little to no matrix. Historically, the very finest examples were reserved for royal and religious use.
From the now-closed Sleeping Beauty Mine in Arizona, this variety is prized for an almost impossibly uniform, pure blue with virtually no matrix at all, making it one of the closest American equivalents to classic Persian turquoise.
Also from Arizona, Kingman turquoise tends toward a blue-green and is well known for its matrix, often a distinctive black, spiderweb-like veining. It's one of the most widely mined and commercially available varieties in the world.
Mined as a byproduct of a former Arizona copper mine, Bisbee turquoise is known for a deep, rich blue set against a dark chocolate-brown matrix, a combination that made it one of the most sought-after and expensive varieties among collectors before the mine closed.
China, particularly Hubei province, has become one of the largest sources of turquoise in the world in recent decades. It ranges widely in both colour and matrix depending on the specific mine, covering almost the entire spectrum from pure blue to strongly green.
Often greener and more porous than the varieties above, Tibetan turquoise carries enormous cultural weight, worn in Tibetan and broader Himalayan jewellery for centuries as a protective and sacred stone, frequently set in silver in ways that have influenced turquoise jewellery design well beyond the region.
Natural, Stabilised and Imitation Turquoise
Because turquoise is a relatively soft, porous stone, much of what's sold commercially has been stabilised, treated with a clear resin that fills its natural porosity, making it more durable and better able to hold a polish. Stabilised turquoise is still genuine turquoise; it's simply been treated to improve its wearability, and reputable sellers disclose when a stone has been treated this way.
Separately, howlite and magnesite, two naturally white minerals, are very commonly dyed blue and sold as an inexpensive turquoise imitation. Dyed howlite can look convincing at a glance, but it isn't turquoise at all, just a different mineral altogether treated to resemble it. If you're buying turquoise specifically for its meaning or its mineral identity, it's worth asking whether a piece is natural, stabilised or an imitation, since all three are common in the market and look similar from a distance.
Turquoise at Symbolia
Our own turquoise collection draws on turquoise's long-held associations with protection, communication and healing, a stone worn across Persian, Native American and Tibetan traditions alike for well over six thousand years. It's also December's birthstone, one of the oldest gemstones still in continuous use anywhere in the world.
Curious how turquoise compares to other stones, or want help finding the right one for you? Our Find Your Stone tool and Science of Crystals guide can help.
Find Your Stone The Science of CrystalsTurquoise Varieties, Answered
Why does turquoise come in different colours?
Turquoise's colour depends on its exact chemistry. Copper produces the blue, while iron, when it substitutes into the mineral's structure in place of aluminium, pulls the colour toward green. Two chemically similar pieces of turquoise can look very different depending on this ratio.
What is the matrix in turquoise?
Matrix is the host rock the turquoise formed within, left behind as veining where the turquoise didn't fully replace the surrounding stone. Dark matrix typically comes from iron or manganese oxides, while golden matrix often comes from the surrounding rhyolite or limestone.
What is the best type of turquoise?
There's no single "best" variety, it depends on taste. Persian and Sleeping Beauty turquoise are prized for a clean, uniform blue with no matrix, while varieties like Bisbee and Kingman are valued specifically for their distinctive matrix patterns.
Is dyed howlite the same as turquoise?
No. Howlite and magnesite are separate, naturally white minerals that are commonly dyed blue to imitate turquoise. They can look convincing but are chemically unrelated to genuine turquoise.
Is stabilised turquoise real turquoise?
Yes. Stabilised turquoise is genuine turquoise that has been treated with a clear resin to fill its natural porosity, improving its durability and ability to hold a polish. It's a treatment, not an imitation.