oxides
Prasiolite
SiO2
- Also known as
- green amethystvermarine
- Crystal system
- trigonal
- Hardness
- 7 on the Mohs scale
- Lustre
- vitreous
- Colour
- Pale leek green
- Where it forms
- Natural material is known from only a handful of localities where amethyst has been altered by geological heating in place.
- Chiefly from
- Montezuma, Minas Gerais, BrazilThunder Bay, Ontario, CanadaLower Silesia, Poland
Why it is that colour
Iron again, in a third arrangement. The colour is unstable enough that natural prasiolite is genuinely rare.
Safety
No hazard from handling.
Where it comes from
Effectively all commercial prasiolite is heat-treated amethyst, mostly from Brazil. The trade name "green amethyst" is discouraged by gemmological bodies precisely because it obscures this.
Historical use
Almost none. Prasiolite entered the market in quantity only after the discovery around 1950 that certain Brazilian amethyst turns green rather than yellow when heated.
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
This stone has essentially no traditional history, because until 1950 there was almost none of it on the market. Meanings attached to it are recent, largely assembled by analogy with green stones generally, and spread online.
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
Prasiolite is included here as a control case. It is a stone with a documented commercial birthday — it appears in quantity in the 1950s because someone worked out what heating a particular Brazilian amethyst does — and yet it now carries a full set of metaphysical properties, presented in the same register and with the same confidence as those attached to stones the Greeks wrote about.
That is informative about the system rather than about the stone. A correspondence tradition that can furnish a complete meaning for a material that did not exist commercially before 1950 is generating meanings rather than transmitting them.
Identity checked against IMA-CNMNC master list, June 2025.