Obsidian cools in hours or days. Granite cools miles underground over thousands to millions of years. This slow cooling allows the identifying crystals to the intrusive, or plutonic, igneous rock forms when magma is trapped deep inside the Earth. Great globs of molten rock rise toward the surface.

It is rocks like obsidian that helped man create window glass: Cooling extremely fast. First attempt was in Edinburgh, Scotland, probably

Dr Michael Issigonis thank you for your contribution to the discussion

Intrusive or plutonic, igneous rock forms when magma is trapped deep inside the Earth. Great globs of molten rock rise toward the surface. Granite is a classic coarse-grained intrusive igneous rock. The different colors are unique minerals. The black colors are likely two or three different minerals. If magma cools slowly, deep within the crust, the resulting rock is intrusive or plutonic. Gabbros are plutonic rocks formed by cooling and crystallization of molten magma trapped under the Earth's surface and chemically equivalent to extrusive basalt. Obsidian cools in hours or days. Granite cools miles underground over thousands to millions of years. This slow cooling allows the identifying crystals to form.Obsidian cooled so quickly that has virtually no crystals. Magma that cools slowly creates rocks with large minerals, like granite. The parts of a volcano include a reservoir of magma inside the Earth is a magma chamber. Obsidian prides itself on performance so if you're experiencing slowness in during normal usage in the app, don't just accept it! There's something that can be done about it. The first thing you'll want to investigate is if the slowness is being caused by a plugin.