Know all about Alkali Feldspar Granite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Alkali Feldspar Granite and Obsidian belong to Igneous Rocks.Texture of Alkali Feldspar Granite is Phaneritic whereas that of Obsidian is Glassy. Alkali Feldspar Granite appears Veined or Pebbled and Obsidian appears Shiny. The luster of Alkali Feldspar Granite is dull to grainy with sporadic parts pearly and vitreous while that of Obsidian is vitreous. Alkali Feldspar Granite is available in black, grey, orange, pink, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Alkali Feldspar Granite are curling, gemstone, laboratory bench tops, tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.