Same radiation that creates your basic Incredible Hulks. You need just these basic ingredients for amethyst to form: pockets or cavities suitable for deposition, silica-enriched water around 50-250☌, a skosh of ferric iron (Fe³+), and gamma radiation.

It's found most places where quartz ends up: in both extrusive and intrusive igneous rocks, in metamorphosed rocks (especially in alpine-type fissures), hydrothermal veins, rocks deposited by hot springs, and even some sedimentary rocks. Good news for those who want a bit of their birthstone for their own selves, isn't it?Įven without those sources, amethyst is fairly easy to track down, even if gem-quality specimens are less abundant. Once those mines started producing, amethyst became available in copious quantities, and now you can buy some really nice specimens for the price of a gourmet coffee or few. It remained an expensive stone, reserved only for the fortunate, right up until ginormous deposits were found in South America in the 1800s. It even ended up in many a country's crown jewels. Rhea the Titan gave it to Dionysus, god of wine, to preserve his sanity from the vine. So, it may shock you just a little bit to learn that gem-quality amethyst used to be considered just as valuable as rubies, celebrated in myth and legend. So, everyone knows amethyst is a purple variety of quartz, yeah? And we're used to it being abundant and fairly inexpensive, aside from those jaw-dropping giant geodes and some really fabulous art. Believe me when I say we'll get there soon, though! So in today's post, we're actually not going to talk much about geodes at all. However, along the way, I got diverted by some very interesting facets of amethysts, including some pretty neato human history. So I decided to go big and explore the origins of those enormous amethyst geodes suitable for making into bathtubs. I must start our foray into this month's birthstone with a confession: I didn't think amethyst would be exciting.

'The stone is an amethyst but I, the tipler Dionysus, say, 'Let it either persuade me to be sober, or let it learn to get drunk.''

Amethyst caves in america