Aventurine

An interesting form of Quartz with a glittering optical effect known as aventurescence, caused by mineral inclusions.

Aventurine can occur in a range of colours, not just green. Green shades are by far the most common colour, though.

It is often used as a decorative stone – either carved or for jewellery making. Polished pieces are the most common, as they do show the colour off better. Rough pieces can look a little white due to surface fractures.

Appearance, Uses and History

Aventurine is a form of Quartz with inclusions that cause a glittering effect known as aventurescence. It is typically used as a decorative or semi precious stone, where it is almost always polished to best show off the sparkles.

The name Aventurine has quite an interesting story behind it. It comes from the Italian term “a ventura” – “by chance”.

It was originally used to describe what we now call ‘goldstone glass’, a form of manmade glass with copper or other metal inclusions. This was originally known as “aventurine glass”, and occasionally still is.

The material was supposedly created as a worker accidentally dropped metal shavings into a batch of glass.

Interestingly, the manmade glass then gave its name to the mineral itself – rather than the other way around.

Locales

Specimens of Aventurine can be found in various locations around the world, including Austria, Brazil, Canada, Chile, India, Russia, South Africa, Spain, Tanzania and parts of the USA. Most of the Aventurine on the market will come from India.

Mineralogy

Chemistry
SiO2 with inclusions of other minerals.
Colours and Variations

Various colours – green is most common. I have also seen pieces in a reddy-brown, pale off-white, orange, red, and even a dark blue.

The colours are caused by various different inclusions:

  • Green – Fuchsite
  • Pink, red, purple – Mica / Lepidolite
  • Pink, orange, red, yellow, brown – Goethite, Hematite
  • Grey, yellow, silver – Muscovite, ilmenite
Streak
Colourless – typically harder than streak plate.
Luster
Naturally quite grainy; when polished it is typically dull to vitreous.
Fracture
Conchoidal, splintery
Transparency
Translucent to opaque.
Crystal habit
Massive
Mohs hardness
6.5 – 7
Specific Gravity
2.64 – 2.69
Fluorescence
N/A
Easiest testing method
Common Treatments
None.

Hazards and Warnings

Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis.

When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.

Translations

May have some overlap with ‘Goldstone’, also known as Aventurine Glass.

Arabic:

  • افينتورين

Hindi:

Portuguese:

  • aventurina

Bengali:

Indonesian:

Punjabi:

English:

  • aventurine

Italian:

  • avventurina

Russian:

  • Зеленый Авантюрин

French:

Japanese:

  • アベンチュリン

Spanish:

  • venturina

German:

  • aventurin

Korean:

  • 어벤츄린

Thai:

  • อเวนเจอรีน

Gujurati:

Mandarin and Traditional Chinese:

Urdu:

Further Reading / External Links

  • https://www.mindat.org/min-436.html
  • https://www.gemdat.org/gem-436.html
  • https://geology.com/gemstones/aventurine/