All of our estimates suggest the crystallization of quartz on time scales of. In igneous rocks, quartz forms as magma cools. Like water that turns into ice, silicon dioxide crystallizes as it cools. Slow cooling generally allows crystals to grow larger.
Not all crystals form in water. Some crystals can form in an element called carbon. However, all crystals are formed in the same way, the atoms come together and become a uniform cluster. The process can take anywhere from a few days to maybe a thousand years.
Natural crystals that come from Earth form in the same way. These crystals formed more than a million years ago within the Earth's crust. They occur when the Earth's liquid consolidates and the temperature cools. Other crystals form when liquid crosses crevices and dispenses minerals to the crevices.
Quartz exists in two forms, normal alpha quartz and high-temperature beta quartz, both of which are chiral. The transformation from alpha quartz to beta quartz occurs abruptly at 573 °C (846 K; 1063 °F). Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks that pass this temperature threshold. The two most common materials in the Earth's crust are silicon and oxygen.
And quartz is made up of these two abundant materials (that is, quartz is the most basic form of silicates found on Earth). Quartz crystals often do not grow continuously, but in short phases. This pulsatile growth is sometimes explained by tectonic activity, which causes a sudden rise of the host rock and a relatively rapid drop in pressure. If you're a novice crystal expert and don't know which crystal to start your journey with, clear quartz is always a good choice to start with.
The formation of new crystals is not inhibited as such, but under conditions of slow growth, larger crystals are favored. Quartz crystals in igneous rocks occasionally show an onion-like internal structure, indicating a pulsating addition of outer layers to the crystals. The most important distinction between types of quartz is the macrocrystalline variety (individual crystals visible to the naked eye) and the microcrystalline or cryptocrystalline variety (aggregates of crystals visible only at high magnifications). Because they are usually the last to form and simply fill the remaining gaps in the rock, ideally shaped quartz crystals are rarely seen in a granite, whereas well-formed feldspar crystals can often be found.
They indicate the balance in the crystal pattern and are an indication that the crystal was allowed to grow without any obstacles. Pure quartz, traditionally called rock crystal or transparent quartz, is colorless and transparent or translucent, and has often been used for hard stone carvings, such as Lothair crystal. Quartz belongs to the tritonal crystal system at room temperature and to the hexagonal crystal system above 573 °C (846 K; 1063 °F). Molecules tend to withdraw from the edges of crystals, and the relationship between the number of edges and the total volume of the crystal does not favor small crystals.
As you may already know, the color of quartz crystals is due to the impurities found in rocks or sand around the crystalline formation.