oxides
Aventurine
SiO2
- Also known as
- Indian jadeaventurine quartz
- Crystal system
- trigonal
- Hardness
- 6.5–7 on the Mohs scale
- Lustre
- vitreous
- Colour
- Green most often; also blue, red and peach
- Where it forms
- As a massive metamorphic quartzite carrying dispersed mica, rather than as crystals.
- Chiefly from
- Karnataka, IndiaBrazilRussiaTanzania
Why it is that colour
Platy mineral inclusions — usually fuchsite, a chromium-bearing mica, for the green. The glitter, called aventurescence, is light reflecting from those flakes.
Safety
No hazard from handling.
Where it comes from
Mined at large scale in southern India. Cheap and abundant; frequently sold as jade.
Historical use
Minor. It is a modern ornamental stone with no significant ancient record.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Little traditional use. The name comes from Italian a ventura, by chance, and it was borrowed from the glass — see below — rather than the other way round. Its modern reputation as a stone of luck and opportunity is essentially a pun on that name, and dates from the modern crystal literature.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Sold as this, but not
Worth knowing
The naming here runs backwards from what people assume. Aventurine glass — the sparkling copper-flecked material now sold as goldstone — was made in Venice first, reportedly after a workman spilled copper filings into a melt by accident. The stone was then named after the glass, because it looked like it.
So a mineral now widely sold for good luck and opportunity carries a name meaning "by chance" that it inherited from a manufacturing accident in a Murano glasshouse. Whatever else that is, it is not an ancient correspondence.
Identity checked against IMA-CNMNC master list, June 2025.