4/28/2023 0 Comments Obsidian blade![]() Tektites were previously believed to be obsidians formed by the eruption of lunar eruptions. Intrusive creation of obsidians occurs when the lava cools beside the dyke’s edge. It is also formed when lava cools once it comes into contact with air or water. ![]() Obsidians forms when the felsic lava cools at the edges of a volcanic dome or felsic lava flow. They can also be located in the eastern US states of North Carolina, Pennsylvania, and Virginia. Obsidian flows that can be hiked are in the Calderas of Lake Medicine Volcano and Newberry Volcano. ![]() They can be found in the United States, Turkey, Scotland, New Zealand, Mexico, Japan, Kenya, El Salvador, Canada, Australia, Armenia, and Argentina. Older obsidians are rare since they are altered or destroyed by heat or weathering. Obsidians are found in places that have experienced recent volcanic activities. The presence of water on the earth’s surface hastens the break down process of the obsidian. Obsidians can break down into some fine-grained mineral crystals with time since it is metastable. They are made up of over 70% silicon dioxide. The transition elements can give them brown, green or tan color. Obsidians are black although their color varies depending on the presence of inclusions or trace elements. It is not a true mineral since it’s not a crystalline solid therefore it’s classified as a mineraloid. Obsidians were used to produce piercing and cutting tools during the stone ages. The curved smooth fractures are formed due to the lack of mineral crystal in the obsidian. Obsidians are brittle and hard volcanic glasses which break with distinctive conchoidal fractures. They are found on the obsidian flows where the high quantities of silica induce a high degree of polymerization and viscosity of the lava that inhibits crystal growth. Obsidians are volcanic glasses referred to as mineraloids. They are formed when felsic lava cools quickly with minimum to no crystal growth. Obsidians are naturally occurring amorphous products of fast cooling magma.
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