Crystal is the most important element of "silica" (sio2), "Si" (silica) is also
composition of the Earth's crust about 65 percent more than most major minerals;
which also contains various trace metals, various colors will cause the crystal
and the crystal will be broad in nature and the various fossil "symbiotic"
together, such as mica, feldspar, calcite, tourmaline and rutile, granite and so
on.
What is the crystal form - crystal growth in the pegmatite deposits and
hydrothermal deposits, the course was more of a middle class in hydrothermal
deposits. We know, deep in the Earth's molten state at a large number of magma.
When affected by tectonic activity, the magma rising influx of Earth's surface -
the crust, in the process, due to temperature, pressure and other conditions
change, did the liquid magma concerning the thermal silica-containing aqueous
solution .
With concentration, composition, etc. constantly changing, in a solution of
saturated or supersaturated state, to a certain space structure (crystal holes)
and the appropriate thermodynamic conditions, silica is spontaneously generated
in solution crystal bud. Or in certain rock conditions germination. Generally
speaking, the more solidified lava cooled slowly, crystals generated by the
greater.