Two hundred and thirteen years ago this May, the Stannern achondrite fell from the sky, landing in what is now the Czech Republic. The shower of stones was reported to have lasted eight minutes which I find astounding for many reasons. Estimates of upwards of 300 individual stones fell with only 66 documented stones recovered, and a majority of those weighed between 32-48 grams. The largest single piece was over 6000 grams, and a total recovered weight around 52 kilograms. At least according to Wikipedia. Oddly, 52kg divided by 66 equals about 788g. So even if 10% of the 66 recovered stones weighed 6kg each, the remaining TKW would average over 270g per stone. So in order for a majority of the 66 recovered stones, let’s say 34 stones for arguments sake, to be 48g or less, even if all 34 stones weighed 48g, that only totals about 1.6kg. So something’s off with the numbers.
However, there is another set of numbers that seems Wikipedia contributors missed, and those numbers are based on original work with the fall. It appears that the 66 total stones and fragments is a common number but the sizes and majorities change drastically. And this earlier set of numbers seems much more inline with the fall history and collection as reported throughout the past two centuries. But a difference among fall numbers from 200 years ago is not unusual.
What is unusual is that there are very few specimens of Stannern today that are complete individuals. And by complete, I mean complete. No windows ground into a face, no sliced off corners, no big chips, dings or scuffs. After 213 years, my guess is that there are less than a dozen truly complete individuals of Stannern on earth. And possibly even less than half a dozen. Every specimen of Stannern I’ve ever seen has some access to its interior. Well, every specimen but one. And that one is in my collection. With a weight at the top end of the Wikipedia majority, my little shiny black stone looks like it fell this morning instead of the morning of May 22, 1808. Every inch is pristine, and each side, corner and edge are just as intact as the moment it touched earth.
As a Eucrite, Stannern may have come from the asteroid Vesta or one of its offspring. The calcium-rich matrix when heated during atmospheric entry makes for a startling jet-black yet shiny tar-like heavily textured fusion crust. A glossy black that is arguably the most beautiful of fusion crusts.
Anyway, the other day I was referencing my Stannern specimen in a online discussion and realized that I never posted pictures of it in any meaningful way. Just one picture of my Stannern has graced Meteorite Times, and that was a long time ago near the end of a long article about many specimens. So here are some images of one of the very few completely intact, fully crusted individuals of the Stannern Eucrite in the world. Enjoy.
Until next time….
