Short answer: aventurine is a translucent quartz rock filled with tiny flat mineral flakes that catch the light and make it glitter, an effect called aventurescence. Green aventurine, colored by flakes of chrome-bearing mica called fuchsite, is the most common. It is sometimes confused with jade and with goldstone, a man-made glass. In crystal traditions it is known as a stone of luck and opportunity.
What is aventurine?
Aventurine is a form of quartzite, a rock made of interlocking quartz grains, rather than a single crystal. What sets it apart are its inclusions: small, flat, platy mineral grains spread through the quartz. When light hits them, they glint like tiny mirrors.
Because it is a rock, its properties vary a little from piece to piece. It is somewhat softer than single-crystal quartz, around 6.5 on the Mohs scale, with a specific gravity of about 2.64 to 2.69.
Why does aventurine sparkle?
The glitter is called aventurescence. It comes from the platy inclusions, mostly mica, lying through the stone. In green aventurine the inclusions are fuchsite, a chrome-bearing variety of muscovite mica, which gives a silvery green or blue sheen. Other inclusions, such as hematite or goethite, give orange and reddish aventurine its color and glint. A high concentration of fuchsite can make aventurine opaque and deep green, so that at first glance it can be mistaken for malachite.
What is fuchsite?
Fuchsite, also called chrome mica, is a chromium-rich variety of muscovite mica. Chromium replacing some of the aluminum in the mica gives it an apple green color, from pale green to emerald green depending on how much chromium is present. It is soft, only 2 to 2.5 on the Mohs scale, and forms flexible flakes. It is named after the German chemist and mineralogist Johann Nepomuk von Fuchs. Fuchsite also fluoresces lime green under long-wave ultraviolet light.
In aventurine, fuchsite occurs as tiny scattered plates inside hard quartz, so the stone as a whole stays far harder than the mica. Pure fuchsite rock is sold too, and it feels soft and flaky by comparison.
What colors are there?
- Green aventurine is the most common and best known.
- Blue aventurine is a less common, blue to blue-green form.
- Orange, brown, yellow and gray aventurine also occur, colored by different inclusions.
- Aventurine feldspar, better known as sunstone, is a different mineral with a similar glitter.
Where does the name come from?
The name comes from the Italian a ventura, "by chance". It alludes to the story that aventurine glass, now called goldstone, was discovered by accident, when a Murano glassworker let copper filings fall into molten glass. The natural stone was named after the glass it resembles, not the other way around: goldstone is one of the few man-made materials to have given its name to a natural stone.
The real story of goldstone
The accident is a good story, but it is a legend. One original method for making goldstone was invented in 17th-century Venice by the Miotti family, who were granted an exclusive license by the Doge, and the earliest documentation dates to 1626. Tales of its discovery by unnamed Italian monks, or by alchemists, have no earlier records to support them, though they explain its folk names "monk's gold" and "monkstone". A goldstone amulet from 12th- to 13th-century Persia, now at the University of Pennsylvania, shows that earlier artisans could make it too.
Making goldstone is demanding. Silica, copper oxide and other metal oxides are melted together so the copper is reduced to metal, then the vat is sealed from the air and held in a narrow temperature range while tiny copper crystals grow. Blue goldstone uses cobalt or manganese, and green goldstone uses chromium oxide.
Where does aventurine come from?
Most green and blue-green aventurine comes from India, particularly around Mysore and Chennai, where it is worked by many artisans. Creamy white, gray and orange material is found in Chile, Spain and Russia. Most aventurine is carved into beads and figurines; finer pieces are cut as cabochons. It is also used as a landscape and building stone.
What is aventurine traditionally associated with?
In modern crystal traditions, green aventurine is known as a stone of luck, opportunity and prosperity, a fitting meaning for a stone whose name means "by chance". It is associated with optimism and new beginnings and is commonly linked with the heart chakra. It is often included in lists of stones for good fortune and abundance.
These are traditions and beliefs. They are part of why people choose aventurine, not properties you can measure in the stone.
Aventurine vs goldstone
Goldstone is a man-made glass filled with tiny metallic crystals, usually copper, that sparkle brightly. It is often golden brown, and also comes in blue and green.
- Goldstone's glitter is too even. The sparkles are distributed in an unnaturally uniform way, and they are bright metallic points.
- Aventurine's glitter is softer and uneven, from flat mica flakes, often in bands, with natural variation in color.
- Goldstone is glass, made by melting silica with copper oxide, not a natural rock.
Goldstone is an attractive material in its own right, but it should be sold as goldstone, not as aventurine.
Aventurine vs sunstone
Sunstone is a feldspar, a different mineral, but it is also known as "aventurine feldspar" because it glitters in a similar way. Its sparkle comes from tiny scales of red copper, hematite or goethite lying parallel inside the crystal, an effect called schiller. Oregon sunstone owes its color to copper. Orange aventurine is quartz; sunstone is feldspar.
Aventurine vs jade
Green aventurine is sometimes passed off as jade. Aventurine glitters when you tilt it in the light; jade does not. The jade guide covers how to identify jade.
Raw, tumbled and polished aventurine
Polishing brings out aventurine's color and sparkle. Most aventurine is carved into beads and figurines, and it is widely sold tumbled and shaped into palm stones, hearts, spheres and towers. Finer pieces are cut as cabochons for jewelry.
How do you care for aventurine?
- Wash it with warm water and mild soap, then dry it.
- Avoid harsh chemicals, which can dull the polish.
- Store it apart from harder stones, since it is a little softer than quartz crystal.
How can you tell real aventurine?
- Tilt it in the light. Real aventurine glints from flat mica flakes inside the stone.
- Look for natural variation: uneven color, bands and patches of denser glitter.
- Check for goldstone: evenly scattered metallic sparkles in glass point to goldstone, not aventurine.
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Frequently asked questions
What makes green aventurine green?
Small flakes of fuchsite, a chrome-bearing mica, spread through the quartz. They give it both its green color and its glitter.
Is aventurine a type of quartz?
Yes. Aventurine is quartzite, a rock made mostly of quartz grains, with flat mineral inclusions that make it sparkle.
What is aventurine traditionally associated with?
In crystal traditions green aventurine is a stone of luck, opportunity and prosperity, and is linked with the heart chakra. These are traditional meanings rather than measurable properties.
Is goldstone the same as aventurine?
No. Goldstone is a man-made glass with metallic crystals. Aventurine is a natural quartz rock. The natural stone was named after the glass, which was being made in Venice by the 17th century.
Can aventurine go in water?
Yes. Aventurine is quartz-based and can be washed with mild soap and water. Dry it afterward.
Sources
- Wikipedia, Aventurine: https://en.wikipedia.org/wiki/Aventurine
- Wikipedia, Goldstone (glass): https://en.wikipedia.org/wiki/Goldstone_(glass)
- Wikipedia, Fuchsite: https://en.wikipedia.org/wiki/Fuchsite
- Geology.com, Quartz: https://geology.com/minerals/quartz.shtml
- Wikipedia, Sunstone: https://en.wikipedia.org/wiki/Sunstone