Geo-Shopping: Aventurine

First of all, spell it with me now: A-V-E-N-T-U-R-I-N-E. Even if Merriam-Webster lists "adventurine," I am a linguistic purist and a pedant: there is just one way to spell this particular word, as far as I'm concerned. It comes from the Latin "a(v) ventura," or "by chance." The story dates only back to 17th century Italian glassmakers who accidentally discovered a new style of glass-making; the glass and the stone do resemble each other, I suppose, but that's pure speculation on my part. The information on the Internet ends there, and alas I don't have my minerals and gemstones guidebook with me.

Aventurine is yet another silicate (SiO₂ aka quartz or quartzite) polymorph, this time of the macrocrystalline variety. That means you can see the crystals with your naked eye. It's a metamorph of sandstone, a sedimentary rock.  The mineral impurities in sedimentary rock determine how the quartz looks during and after the metamorphosis; green aventurine comes from chromium present in the original sandstone, while "red" aventurine contains hematite (Fe₂O₃) or goethite (FeO(OH))—in other words, iron-bearing minerals.


Green is the most common, but "red" is easy to find as well. And I have both!

Red aventurine

Green aventurine

Both aventurines made it into the Mad Scientists of Etsy's April/May challenge piece, which was a science news story about the discovery of the world's tinest vertebrate: a frog in New Guinea that grows to seven millimeters in length. Those beads you're looking at up there are eight millimeters  in diameter, the perfect size for such a tiny frog to perch upon! They are also both colors I think of when I think of frogs and toads: green, brown, orange, and so forth.

Naturally, I had to represent such a small animal with a number equally small. What better than the radius of an electron?

"Tiny Frog" electron radius cuff bracelet

"Tiny Frog" electron radius necklace

Imagine a whole string of frogs around your neck like that!