Curio Cabinet: Obsidian

CC obsidian

The Curio Cabinet series (#curioTuesday) is published biweekly, featuring an artifact of natural or cultural history and a brief selection of nifty facts. Curio Cabinet celebrates the history of curio collections, the roots of which played a part in the globalization of learning and scientific knowledge. Learn more here.

Today’s curio: obsidian
Type: mineral
Origin: central/eastern Oregon, USA
Size: about 5 in wide x 3 in tall

Obsidian is an amazing stone, because it’s actually glass. A type of volcanic lava, it cools so quickly after surfacing that it does not form internal crystalline structures. This is what makes it a glass rather than a true mineral. Jim Miller, B.Sc., M.Sc. Geology, calls it more of a “congealed liquid.” It’s hard, brittle, and can fracture with monstrously sharp edges.

Usually obsidian presents varying degrees of black, but when other minerals find their way into its composition, it can display an impressive range of colors. The one pictured above with the reddish bands is called mahogany obsidian, and it gets it color from hematite or limonite (which contain iron). This specimen was a gift from a friend, collected from one of several sites in central Oregon where rockhounds can go crazy. Obsidian can also come in shades of blue, green, silver, transparent, and rainbow (although be aware that fake obsidian is being manufactured in these colors too, if you’re interested in collecting).

Rainbow obsidian from

Obsidian was first used as a tool almost a million years ago and remained a highly valued resource for use in hunting and food preparation, as it could be used to puncture, slice, and even cut through bone. It was therefore a very special item in indigenous trade, particularly in the Americas. The large point on the right side of the image was gifted to me by a hobby knapper.

Today, science is experimenting with obsidian for contemporary medicine: a study published in 1982 expressed the value of using obsidian blades over steel blades. Steel, even at its sharpest, still has a rough edge when magnified significantly. Obsidian, on the other hand, maintains an incredibly smooth edge, which reduces the amount of trauma inflicted upon soft tissue during surgery.

In Oregon, there’s an amazing shield volcano called Newberry National Volcanic Monument, where you can visit 50,000 acres of forest, lakes, and a spectacular geologic formation known as the Big Obsidian Flow. The Big O is only 1300 years old – the youngest in the state – but features a hike right through the solid mass of black glass. When I visited, I was so blown away by this interpretive sign illustrating the difference between a steel scalpel and an obsidian one that I snapped a picture of it:

obsidian sign


Surface obsidian on the Big Obsidian Flow trail at Newberry Monument, Oregon.

obsidian trail

A human-sized chunk of obsidian, Newberry National Volcanic Monument.

A seriously tough little tree growing in a field of volcanic glass, Newberry National Volcanic Monument.

Thanks for joining us for #curioTuesday! Interested in having something from your collection featured? Email us with a bit about yourself and your curio.

Posted on April 22, 2014, in Curio Collection and tagged , , , , , , , , , , , , , , , , , , , . Bookmark the permalink. Comments Off on Curio Cabinet: Obsidian.

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