I captured a long-exposure, time-lapse video of the Aurora Borealis visible from central Oklahoma, USA the other night.

#Oklahoma, #photography, #AuroraBorealis

This is a piece of malachite (Cu2CO3(OH)2), a copper-containing mineral that has been used as a pigment, a copper ore, stonecarving, and decoration for many thousands of years.

The striping comes from t
being chemically-precipitated from mineral-rich water.

#minerals #geology #coolrocks

Copper nuggets like this piece from Michigan, USA, were tilled up and deposited on the surface by glacial activity some 14,000 years ago and provided several native cultures in North America with a great source of raw metal without mining or smelting.

#Michigan #metallurgy #geology #Nativehistory

The colors on that bismuth crystal from the last post are due to thin layers of oxide interfering with the wavelength of reflected light.

The pure metal itself is naturally silvery looking, like the interior of this broken block of bismuth.

#earth #elements #chemistry #crystals

Bismuth crystals like this form naturally under the right conditions when molten bismuth cools, though these conditions rarely, if ever, exist in nature.

The myriad of colors is due to oxide layers on the surface, the metal is naturally silvery in color.

#earth #elements #chemistry #crystals

I have a backlog of items, mostly fossils to digitize and upload to sketchfab, including this Pennsylvanian (323.4-298.9 mya) plate full of fossil seed fern and giant horsetail bits.

#fossils #paleontology #paleobotany