Since obsidian is of volcanic origin it could be found wherever there is or has been volcanic activity. Some important sources are: Arizona, Utah, New Mexico, Hawaii, Oregon, Japan, Mexico, the Indonesian island of Java, Guatemala, Iceland, Ecuador, and Italy’s Lipari Islands.
Another famous source of obsidian is Yellowstone National Park in the state of Wyoming. Many scientists assume that there was a volcanic eruption there many years ago, so it makes sense that one can find obsidian there. (There is actually a large outcrop of the stone in the park called “Obsidian Cliff.”) I myself found two nice pieces of obsidian in Yellowstone when my family and I went there last year. One was a nice glassy, black, translucent chip about the size of a quarter and the other was a black, nearly opaque, broken lump with beautiful spheres of white minerals in it, one of which was exposed by a break. Unfortunately, I couldn’t add these to my collection because it is illegal to remove minerals from a national park! I was, however, able to photograph them and I’ve used the photo of the little chip as this post’s picture.
Next week I will make my final obsidian post (for now, anyway) which explores obsidian’s curious properties.
As you have probably noticed, I usually don’t break minerals into separate posts. Usually I try to contain all of the information that I know about each mineral, rock, or fossil into one post by condensing my writing or by writing a really long post. That isn’t going to work with obsidian, simply because there is a lot to say about it. That is why I plan to blog about obsidian in three or four posts.
Obsidian is a kind of natural glass that is made when lava cools so quickly that no crystals can form inside of it. Since no crystals can form in obsidian it is amorphous, meaning that is has no crystal structure. Obsidian is composed mostly of quartz and has the same vitreous luster, but it is lighter and softer than quartz (this is because of the way its molecules are arranged.) Obsidian is often black in color, but it can also be mahogany-colored, golden, dark green, gray, greenish-black, yellow, brown, iridescent, and reddish-brown. Iridescent obsidian is also called “rainbow obsidian.” Obsidian can also contain white crystals of the mineral christobalite that look like snowflakes and is therefore called “snowflake obsidian.” Sometimes the colors mentioned above will mix to form obsidian with swirls and patches of different colors. Obsidian is translucent, but thin pieces can appear to be transparent and thick pieces can appear to be opaque.
After reading this post (which merely covers the basic facts about obsidian) you can probably see why I had to break obsidian into more than one post!
.jpg)
