Obsidian, Through The Lava Flow
Part of why I started my site was a quest for knowledge. I did a bit of research on pumice and it lead to several other areas of interest. One of them was other bi-products of volcanic activity. One that I have been mulling about in my mind is obsidian. I have read quite a few books in which obsidian is used as a cutting tool or used in some kind of ritual. It appears to be a multi-purpose tool.
Obsidian is made by volcanic lava coming in contact with water. As the lava pours into the body of water, it cools quickly. This rapid cooling produces a rock with a glassy texture. The iron and magnesium content of lava determines the color, which ranges from dark green to black.
Obsidian is often confused with smoky quartz. They have similar properties because of the similar chemistry but obsidian lacks crystalline structure. Have you heard of quartz crystals? The piezoelectric (the generation of stress in such crystals subjected to an applied voltage) and optical properties present in quartz are absent in obsidian.
The hardness of obsidian is between 5 – 5.5. By comparison, talc has a hardness of 1, quartz has a hardness of 7, and a diamond has a hardness of 10. Although quartz and obsidian are basically the same chemical composition, SiO2 (silicon dioxide), obsidian’s lack of crystal structure allows it to be shaped into the cutting tools or decorative objects used by primitive cultures. Its translucent nature gives it a glass like appearance that makes it prized for decoration and ceremonial purposes. It was extensively traded by primitive cultures and can be found in archeological excavations very distant from any known source.
That is the beauty of a little knowledge. You never know where you are going to end up.
Icool
Cobb
Obsidian is made by volcanic lava coming in contact with water. As the lava pours into the body of water, it cools quickly. This rapid cooling produces a rock with a glassy texture. The iron and magnesium content of lava determines the color, which ranges from dark green to black.
Obsidian is often confused with smoky quartz. They have similar properties because of the similar chemistry but obsidian lacks crystalline structure. Have you heard of quartz crystals? The piezoelectric (the generation of stress in such crystals subjected to an applied voltage) and optical properties present in quartz are absent in obsidian.
The hardness of obsidian is between 5 – 5.5. By comparison, talc has a hardness of 1, quartz has a hardness of 7, and a diamond has a hardness of 10. Although quartz and obsidian are basically the same chemical composition, SiO2 (silicon dioxide), obsidian’s lack of crystal structure allows it to be shaped into the cutting tools or decorative objects used by primitive cultures. Its translucent nature gives it a glass like appearance that makes it prized for decoration and ceremonial purposes. It was extensively traded by primitive cultures and can be found in archeological excavations very distant from any known source.
That is the beauty of a little knowledge. You never know where you are going to end up.
Icool
Cobb
posted by Cobb at
6:28 AM
0 Comments:
Post a Comment
<< Home