What is opal is it quartz?
Opal is not a kind of quartz, but like quartz, it’s made of silica, which is silicon dioxide, which can also be a glass. Opal’s internal structure takes the form of tiny spheres stacked together. Quartzes (there are almost an infinite number of varieties of quartz) form in the trigonal subdivision of the hexagonal crystal system, whose basic building blocks are of specific angular shapes. Glasses are truly amorÂphous, without a regular internal structure, or about the same internal “structure” as a blob.
