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Brown Streaky Obsidian

Submit an Entry: My Igneous Rock

By Cathy Hennessy

Brown Streaky Obsidian

Central Calif Obsidian

Where This Rock Is From (place, type of locality, etc.)

Central Coast California, San Simeon Beach.

What This Rock Is

Igneous, obsidian with some type of external coating.

What I Like About This Rock

While the core of the rock appears to be solid obsidian. The external coating has striations that take on the appearance of petrified wood.

I was visiting Paso Robles, California and spent the day at the beach. I found several interesting and very different rocks. When I first picked this sample up I thought it was a piece of petrified wood. Then I noted that the purplish/black glassy core. It also has some rust colored bands on the exterior on several sides. Each facet of the angular rock presents an interesting and different appearance. It is a fun conversation piece.


  • This rock is fun to handle and turn since all the sides present different facets.
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