Quartz Crystal is a naturally occurring mineral
with an impressive range of colors and inclusions. It is the second most
common mineral on Earth, with the chemical formula SiO2 (Silicon Di-Oxide). On
a chemical level Quartz is identical to glass, being that glass is made
out of sand, and sand is what happens to quartz when the earth does
it’s normal, brutal, routine on it. The only real difference is the fracture pattern, and some places have begun faking exceptional quartz "specimens" with cut, polished, glass.
The major categories are Macrocrystalline (Crystals) and Microcrystalline/Cryptocrystalline
(Masses). Dozens upon dozens of other minerals are technically nothing
more than Crypto Quartz with an inclusion or impurity composed
of another mineral.
Macrocrystalline Quartz also comes in a bajillion formations (often
called “configurations") which are said to subtly alter the “energy" of
the crystal and may include other mineral types (as above) rendering a
lot of data and types and far more waffling and wall-feeling on the
matter. Right now, I have balanced on my knee a gigantic mofo of a book
(hint: It’s purple) with 80 pages dedicated simply to “quartz"
(macrocrystalline). Lots of waffling.