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BIF: banded iron formation

A BIF is a ~2-3.7 billion year old sedimentary rock that has alternating layers of grey hematite or magnetite and red chert. These rocks formed when earths atmospheric oxygen was around 1/10 of what it is today and only form under such conditions. The genesis of oxygen producing microorganisms also caused the extinction of BIF’s when the earth had a more abundant oxygen supply.

Feb 5
Can someone help me identify this rock?

Can someone help me identify this rock?

Uvarovite garnet from Russia

What is this mineral?!?!?

Vanadinite

Mohs hardness: 3

colors: orange-red and yellow

Vanidinite is a secondary mineral, forming from oxidized ore deposites containing lead. It is a major source of the element vanadium. It also usually shows perfect hexagonal crystals.

Got some vanidinite and cinnabar

Will post soon

Oct 9
More fluorite

More fluorite

Oct 9
Rosasite with calcite

Rosasite with calcite

Corundum

Colors: many

Mohs hardness scale: 9 (defining mineral)

Also know as ruby or sapphire. (polished ruby shown on the right) only the red variety of corundum is called a ruby, while sapphire’s are every other color. Corundum is used in high temperature ceramics, an abrasive for polishing metal and has been made into sandpaper.

Corundum

Colors: many

Mohs hardness scale: 9 (defining mineral)

Also know as ruby or sapphire. (polished ruby shown on the right) only the red variety of corundum is called a ruby, while sapphire’s are every other color. Corundum is used in high temperature ceramics, an abrasive for polishing metal and has been made into sandpaper.

Aug 6

Aragonite

colors:colorless, white, gray, yellowish, reddish, green

Mohs hardness: 3.5-4

Named after where it was first found, the Aragon region of Spain. Aragonite is a polymorph of calcite (meaning that it is made up of calcium carbonate, the same exact chemical composition as calcite, but both of these minerals have different crystal structures.)