Hardness: 5 – 5.5
Unlike crystals that grow in the ground and have a crystalline structure, most obsidian is formed when the very hot lava (a mixture of mostly silicate minerals and sand) erupts from the volcano, comes in contact with a cooler atmosphere and / or water and cools quickly.
When cut or broken, obsidian glass can have very sharp edges which explains why spearheads, arrowheads, knives and other instruments of years ago were made out of obsidian. Today, obsidian is used to make medical scapels.
Most obsidian is black due to its high content of magnesium and iron. Since obsidian is made up of approximately 30% of impurities, it can be many colors. (We have black, yellow, blue, and aqua obsidian tumbles).
There are various types of obsidian. Rainbow obsidian has iridescent rainbows hues or effects. This can either be caused by tiny gas bubbles in the lava that got trapped or the various inclusions within the lava cooling at different rates. Regardless, it is quite an optical phenomena!
Snowflake obsidian has white or grayish “snowflake” markings created by cristobalite.
Sheen Obsidian is caused by gas bubbles giving off a golden hue.
Apache Tears are black obsidian mixed with perlite.
Interesting Tidbits: Obsidian, named after the Roman explorer “Obsius” is natural glass. According to legend, Obsius brought the first piece of obsidian to Rome from Ethiopia.
It is often difficult to tell the difference between obsidian and onyx. Since obsidian is volcanic glass, it has a glossy appearance and usually weighs less than onyx. For more information on how to tell the difference between obsidian and onyx, please check out our blog. Our link is below.
http://www.crystalsandgemstones.com/category/our-blog/page/5/
Obsidian Tumbles (Yellow)
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Snowflake Obsidian Hearts
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Snowflake Obsidian Spheres
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Snowflake Obsidian Tumbles
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