Obsidian is a rock which is a type of naturally occurring glass produced by volcanoes. It lacks crystal structure, which can make it have extremely thin edges. This is the reason why obsidian was often used as arrowheads in a variety of ancient cultures. This particular example of obsidian features intricate spiderweb patterning, caused by thermal (during the cooling process) and physical stress. It's large enough to serve as a paperweight, and makes for a great sample to be passed around in earth science classrooms. Makes a great gift for the mineral collector in your family!
Note: Please be aware that this is a natural mineral and as such each piece is one of a kind! The one you receive may not be exactly the same as the ones pictured but it will be similar. Price is per each piece. They come in irregular shapes, sizes and weights.
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