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Edziza obsidian found in coastal areas of southeast Alaska. Edziza obsidian is a naturally formed volcanic glass found at the Mount Edziza volcanic complex in northwestern British Columbia, Canada. It occurs in at least four geological formations of the volcanic complex and was widely used by indigenous peoples during the pre-Columbian era.
Successive eruptions eventually built the volcanic pile above lake level to form a small temporary island that produced subaerial lava flows and lava fountains. [109] The result of this volcanism was the creation of Pillow Ridge on the northwestern flank of Mount Edziza, so-named for its exposures of pillow lava.
Gyali (Greek: Γυαλί "glass", also spelled Giali or Yali, pronounced ) is a Greek volcanic island in the Dodecanese, located halfway between the south coast of Kos and Nisyros. It consists of rhyolitic obsidian lava domes and pumice deposits (which are mined in huge quantities).
The source of obsidian for cultures inhabiting the territory of and around Greece was the island of Milos; the Starčevo–Körös–Criș culture obtained obsidian from sources in Hungary and Slovakia, while the Cardium-Impresso cultural complex acquired obsidian from the island outcrops of the central Mediterranean.
Like the rest of the cluster, the island is of volcanic origin, with tuff, trachyte and obsidian among its ordinary rocks. Volcanic activity began 2 to 3 million years ago during the Pliocene, and last erupted 90,000 years ago during the Pleistocene, and is considered to still be a dormant volcano that could erupt again.
The island is considered special by Māori (the indigenous people of New Zealand) partly because of the presence of black obsidian, a volcanic glass created by the rapid cooling of silica-rich lava, prized as a cutting tool. The obsidian was called Tūhua by Māori, who called the island by the same name.
Kōzu-shima is a compound volcanic island 6 km in length with a maximum width of 4 km. The island is formed from a cluster of eighteen lava domes , with rhyolite and pyroclastic ash deposits. The highest of these lava domes, Tenjō-san ( 天上山 ) , has a height of 571 metres (1,873 ft), and was last active in 838 AD per the ancient Japanese ...
Caldera and bay of Yankicha. Ushishir (Russian: Ушишир; Japanese: 宇志知島; Ushishiru-tō; Ainu: ウシシㇼ, lit."Land of the bay") is a collective name for two uninhabited volcanic islands and several reefs, all being parts of an eponymous partially submerged volcano, located in the centre of the Kuril Islands chain in the Sea of Okhotsk in the northwest Pacific Ocean.