Blue, Purple and Violet Minerals

The most common and significant ones

The blue, violet and purple end of the visible spectrum is not one where rocks and minerals are commonly found. In the field, you are unlikely to see minerals in this color range unless you are in one of four settings (in order of abundance):

  1. Pegmatites 
  2. Certain metamorphic rocks 
  3. Oxidized zones of ore bodies 
  4. Low-silica (feldspathoid bearing) igneous rocks 

This list is for minerals that are typically or most characteristically blue, violet, purple or related shades. While many of these minerals are easily found in rock shops, they are not as common in the field. A good geologist may see only half of these during their career in the field. 

To properly identify your blue, purple or violet mineral, you need to first inspect it in good light. Decide the best name for its color—the colors of the minerals in this list include blue-green, sky-blue, lilac, indigo, violet and purple. In translucent minerals, blue color is less reliable than in opaque minerals. At the same time, note the mineral's hardness and its luster on a fresh surface. If possible, determine the rock class—igneous, sedimentary or metamorphic—and the more specific rock type as well as you can (see "How to Look at a Rock" for starting guidance).

01
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blue apatite
Apatite. PHOTOSTOCK-ISRAEL / Getty Images

Apatite is an accessory mineral found as crystals in many pegmatites. It is often blue-green to violet, although it has a wide color range from clear to brown befitting its wide range in chemical composition. Apatite is commonly found and is used for fertilizer and pigments. Gemstone-quality apatite is rare, but does exist. 

Glassy luster; hardness of 5. Apatite is one of the standard minerals used in the Mohs scale of mineral hardness

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Cordierite

Cordierite
Cordierite. David Abercrombie / Flickr / CC BY-SA 2.0

An accessory mineral of high-magnesium, high-grade metamorphic rocks like hornfel and gneiss, cordierite forms grains that display a shifting blue-to-gray color as you turn it. This unusual feature is called dichroism. If that isn't enough to identify it, cordierite is commonly associated with mica minerals or chlorite, its alteration products.

Glassy luster; hardness of 7 to 7.5.

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Close up of Dumortierite
Dumortierite. DEA/R.APPIANI / Getty Images

This uncommon boron silicate occurs as fibrous masses in pegmatites, in gneisses and schists, and as needles embedded in knots of quartz in metamorphic rocks. Its color ranges from light blue to violet.

Glassy to pearly luster; hardness of 7. 

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Glaucophane
Glaucophane. Graeme Churchard / Flickr / CC BY 2.0

This amphibole mineral most often is what makes blueschists blue, although bluish lawsonite and kyanite may also occur with it. It is widespread in metamorphosed basalts, usually in felted masses of tiny needlelike crystals. Its color ranges from pale gray-blue to a "blue-jean" indigo.

Pearly to silky luster; hardness of 6 to 6.5.

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Blue kyanite
Blue kyanite crystals in groundmass. Gary Ombler / Getty Images

Aluminum silicate forms three different minerals in metamorphic rocks (pelitic schist and gneiss), depending on the temperature and pressure conditions. Kyanite, the one favored by higher pressure and lower temperature, typically has a mottled light blue color. Besides the color, kyanite is distinguished by its bladed crystals with a unique property of being much harder to scratch across the crystal than along its length.

Glassy to pearly luster; hardness of 5 lengthwise and 7 crosswise.

06
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Lepidolite silicate
Lepidolite. De Agostini Picture Library / Getty Images

Lepidolite is a lithium-bearing mica mineral found in select pegmatites. Rock-shop specimens are invariably lilac colored, but it may also be grayish green or pale yellow. Unlike white mica or black mica, it makes aggregates of small flakes rather than well-formed crystalline masses. Look for it wherever lithium minerals occur such as colored tourmaline or spodumene.

Pearly luster; hardness of 2.5.

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Oxidized Zone Minerals

Azurite
Azurite. lissart / Getty Images

Deeply weathered zones, especially those at the top of metal-rich rocks and ore bodies, produce many different oxides and hydrated minerals with strong colors. The most common blue/bluish minerals of this type include azurite, chalcanthite, chrysocolla, linarite, opal, smithsonite, turquoise and vivianite. Most people will not find these in their own neighborhood, but any decent rock shop will have them all.

Earthy to pearly luster; hardnesses 3 to 6.

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Amethyst, Oxide
Amethyst. De Agostini Picture Library / Getty Images

Purple or violet quartz—named amethyst as a gemstone—is found crystallized as crusts in hydrothermal veins and as secondary (amygdaloidal) minerals in some volcanic rocks. Amethyst is quite uncommon in nature, and its natural color may be pale or muddled. Iron impurities are the source of its color, which is heightened by exposure to radiation.

Glassy luster; hardness of 7.

09
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Sodalite
Sodalite in rock groundmass. Harry Taylor / Getty Images

Alkaline low-silica igneous rocks may have large masses of sodalite, a feldspathoid mineral that usually has a rich blue color, also ranging from clear to violet. It may be accompanied by the related blue feldspathoids hauyne, nosean and lazurite.

Glassy luster; hardness of 5.5 to 6.

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Spodumene
Spodumene. Géry Parent / Flickr / CC BY-ND 2.0

A lithium-bearing mineral of the pyroxene group, spodumene is restricted to pegmatites. It's typically translucent and commonly takes on a delicate lavender or violet shade. Clear spodumene can also be a lilac color, in which case it is known as the gemstone kunzite. Its pyroxene cleavage is combined with a splintery fracture.

Glassy luster; hardness of 6.5 to 7.

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Other Blue Minerals

Benitoite
Blue benitoite crystals and white natrolite in rock groundmass. Harry Taylor / Getty Images

There are a handful of other blue/bluish minerals that occur in various uncommon settings: anatase (pegmatites and hydrothermal), benitoite (one occurrence worldwide), bornite (bright blue tarnish on a metallic mineral), celestine (in limestones), lazulite (hydrothermal), and the tanzanite variety of zoisite (in jewelry).

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Off-Color Minerals

Blue topaz crystal in pegmatite groundmass
Blue topaz crystal in pegmatite mass. Harry Taylor / Getty Images

A large number of minerals that are usually clear or white or other colors may be occasionally found in shades from the blue to violet end of the spectrum. Notable among these are barite, beryl, blue quartz, brucite, calcite, corundum, fluorite, jadeite, sillimanite, spinel, topaz, tourmaline and zircon.

Edited by Brooks Mitchell