What is the difference between granite and rhyolite

The difference is rhyolite has much finer crystals. ... Rhyolite is an extrusive igneous rock having cooled much more rapidly than granite giving it a glassy appearance. The minerals that make up rhyolite are quartz, feldspar, mica, and hornblende. Gabbros are dark-colored, coarse-grained intrusive igneous rocks.

This is from the website volcano.oregonstate.edu/book/export/html/1055

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.