Obsidian is a naturally occurring, volcanic glass formed when silica-rich lava cools rapidly.
This rapid cooling is why obsidian is not crystalline, and therefore not a true mineral, though it is sometimes classified as a mineraloid.
Unlike intrusive minerals that take thousands of years to form from magma cooling inside the Earth, obsidian is an extrusive rock, which means it forms after being erupted.
It typically occurs black, but if other minerals are present during formation they can sometimes add color to the glass. In the case of mahogany obsidian, iron-rich hematite and magnetite add reddish streaks throughout which can resemble mahogany timber.
Obsidian can have very sharp edges; in fact, obsidian blades can be made much sharper than steel surgical scalpels.
The photos are representative of what you might receive; please allow for variation.
Collections containing this item: Bestsellers | Geology | Items ≤ $20 | Newest Listings | Rocks, Crystals, & Minerals | Sale Items |
Item as described, packaged very thoughtfully with a great information card
Very good size specimen, with nice colors and edges. If you buy one, remember this IS obsidian: the edges can be very sharp! These used to be used for knife blades and spears! Very happy with the purchase and the service.
Very nice specimen. Well packed, and very quickly shipped!
Hannah rated this 5 stars on Etsy
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