Opal

==//opal is a amorphous sio2'nh2o hydrated silicon dioxide. opal has many many colors white, milky blue, just plain blue, gray, yellow, green, brown, and most important black. opal is mostly found in Australia. the hardness of opal is between 5.5 and 6. the uses for opal are its used in earnings necklaces and rings. opals luster is vitreous-dull. the streak of opal is white. opal density is 1.9 to 2.3 but it averages out to 2.09. the crystal system for opal there actually is no crystal system. the cleavage and fracture for opal there is no cleavage but fracture is smoothly curving surfaces. opal characteristics re that it has many many colors it can be all sorts of different colors, it is also the birth stone of Oct. opal is not really found in Iowa but u can find it in jewelry stores.//==