To view all our multimeter ranges go to http://bit.ly/1EdnDeo. In this video, Josh shows us how to use a multimeter to check for faults in an electrical switch.1  Howto & Style. 2  Standard YouTube License.o view all our multimeter ranges go to http://bit.ly/1EdnDeo. In this video, Josh shows us how to use a multimeter to check for faults in an electrical switch. 1  Howto & Style. 2  Standard YouTube License.
Black is the most common color of obsidian. However, it can also be brown, tan, or green. Rarely, obsidian can be blue, red, orange, or yellow. The colors are thought to be caused mainly by trace elements or inclusions.
Obsidian, natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass. Though obsidian is typically jet-black in colour, the presence of hematite (iron oxide) produces red and brown varieties, and the inclusion of tiny gas bubbles may create a golden sheen.