Diatomite
“A rock made of glass skeletons”
Sedimentary
Diatomite (diatomaceous earth) is a soft, siliceous sedimentary rock composed almost entirely of the fossilized remains of diatoms — microscopic algae with intricate glass-like cell walls. A single cubic centimeter can contain millions of these tiny fossils.
Composition
amorphous silica (opal-A from diatom frustules)
Where Found
Lompoc (California, USA), Denmark, Kenya's Rift Valley, China
Mohs Hardness
1-1.5
Fun Fact
Alfred Nobel used diatomite to stabilize nitroglycerin, creating dynamite — one of the most profitable inventions in history.
Test Your Knowledge
Why is diatomite so effective as a filtration material in pools and breweries?
Related Specimens
Want to identify rocks yourself?