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What Is Smoky Quartz? Meaning, Color and Properties

By Digital Towns Crystals ยท Last reviewed October 7, 2026

Short answer: smoky quartz is a brown to black variety of quartz, ranging from almost transparent to nearly opaque. Its color comes from natural radiation in the surrounding rock acting on traces of aluminum in the crystal. It rates 7 on the Mohs scale, making it durable for jewelry. Very dark, opaque smoky quartz is called morion, and Scottish smoky quartz is known as Cairngorm. In crystal traditions it is a classic grounding stone.

What is smoky quartz?

Smoky quartz is silicon dioxide, the same mineral as clear quartz and amethyst, in a brown, smoky gray or nearly black form. It ranges in clarity from almost completely transparent to almost opaque. It is popular both as a gemstone and as a collectible crystal, and it forms the same six-sided points and clusters as clear quartz.

What makes smoky quartz smoky?

Its color is produced when natural gamma radiation, given off by the surrounding rock, activates "color centers" around aluminum impurities in the quartz. Quartz without that radiation, or without the aluminum, stays clear.

Crystals that grew in some environments, such as pegmatites and alpine fissures, tend to be evenly colored. Crystals from other settings often show color zoning or phantoms, ghostly outlines of earlier growth stages inside the crystal. In some crystals the color is darker near the edges.

Does smoky quartz fade?

It can. Smoky quartz fades if it is heated or exposed to ultraviolet light. Heated, it may turn a pale yellow resembling citrine, and some heat-treated smoky quartz is sold commercially as citrine. Gamma irradiation can restore the color to faded crystals, which is why some smoky quartz on the market has been artificially irradiated.

What are morion and Cairngorm?

  • Morion is a very dark brown to black, opaque variety of smoky quartz. It is also the German name for smoky quartz. The name comes from a misreading of the word mormorion in Pliny the Elder.
  • Cairngorm is smoky quartz from the Cairngorm Mountains of Scotland. It is usually a smoky yellow-brown, sometimes grayish brown, and it is used in Scottish jewelry, on kilt pins and on the handles of the small knife called a sgian-dubh.

A brief history

Smoky quartz is common and was not historically important as a gem, but in recent times it has become popular, especially for jewelry. One unusual early use: flat panes of smoky quartz were used as sunglasses in China in the 12th century.

In the United States, smoky quartz has been the state gem of New Hampshire since 1985.

Smoky quartz and its quartz relatives

Smoky quartz is one of several colored forms of the same mineral, each colored in a different way:

  • Clear quartz, or rock crystal, is quartz without color centers or inclusions to tint it.
  • Amethyst is purple, from natural irradiation acting on traces of iron. See the amethyst guide.
  • Citrine is yellow. Natural citrine is rare, and most citrine sold is heat-treated amethyst or, sometimes, heat-treated smoky quartz.
  • Smoky quartz is brown to black, from natural radiation acting on traces of aluminum.

Not every brown quartz is colored this way. Herkimer diamonds, for example, can look smoky because of tiny particles of hydrocarbon trapped inside, not color centers.

All quartz, smoky included, is piezoelectric: it develops an electric charge when squeezed. Jacques and Pierre Curie discovered this property in 1880, and one of its most common uses today is the quartz crystal oscillator, which keeps time in clocks and electronics.

Smoky quartz vs black tourmaline and obsidian

Dark smoky quartz, especially morion, can be confused with two other black stones.

  • Black tourmaline (schorl) forms long crystals with a rounded triangular cross-section and lengthwise grooves. Quartz crystals are six-sided. See the tourmaline guide.
  • Obsidian is natural volcanic glass, formed when lava cools too quickly for crystals to grow, so it never shows crystal faces.
  • Smoky quartz forms six-sided crystals with pointed ends, and all but the darkest crystals are at least translucent.

What is smoky quartz traditionally associated with?

In modern crystal traditions, smoky quartz is one of the best-known grounding stones, associated with stability, calm and letting go of negativity. It is commonly linked with the root chakra and with protection, and it is often named as a stone for Capricorn.

These are traditions and beliefs. They are part of why people choose smoky quartz, not properties you can measure in the crystal.

Raw, tumbled and polished smoky quartz

Smoky quartz is sold as natural points and clusters, often still showing their glassy faces and phantoms, and polished into points, towers, spheres, hearts and tumbles. Clear, evenly colored material is faceted for jewelry.

Smoky quartz jewelry

At 7 on the Mohs scale, smoky quartz is durable enough for rings, necklaces, bracelets and earrings. Its popularity as a jewelry stone is recent, and it is commonly faceted to show off its transparency.

How do you care for smoky quartz?

  • Keep it out of strong sunlight and away from heat, both of which can fade it.
  • Wash it with warm water and mild soap, then dry it.
  • Store it apart from harder gems such as sapphire and diamond, which can scratch it.

How can you tell natural smoky quartz?

  • Natural color is often uneven in crystals from many settings, with zoning, phantoms or darker edges.
  • Check hardness: quartz is 7 on the Mohs scale, harder than glass and steel, so a steel blade will not scratch it.
  • Ask about treatment. Irradiation is common and should be disclosed.

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Frequently asked questions

What gives smoky quartz its color?

Natural gamma radiation from surrounding rocks activates color centers around aluminum impurities in the quartz, turning it brown to black.

Does smoky quartz fade in the sun?

It can. Ultraviolet light and heat both fade smoky quartz, so keep it out of strong sunlight.

What is smoky quartz traditionally associated with?

In crystal traditions it is a grounding and protection stone, linked with the root chakra and Capricorn. These are traditional meanings rather than measurable properties.

What is the difference between smoky quartz and morion?

Morion is the very dark, nearly black, opaque form of smoky quartz.

Is smoky quartz rare?

No. Smoky quartz is a common variety of quartz, though it has become a popular gemstone in recent times.

Is smoky quartz a state gem?

Yes. It has been New Hampshire's state gem since 1985.

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