A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but the extreme range of values suggested is 1 to 200 microns.
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Copper(I) oxide in the context of Copper (II) oxide
Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite, or sometimes black copper. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.
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