When the magma cools down, the atoms are linked together in crystalline patterns, and thus different minerals are formed. When this process happens deep inside the earth, rock formations can happen on a pretty large scales. The Igneous rocks are formed by magmatic processes of the earth. This forms really large crystals of rare minerals. But this can happen only in the right conditions. Rock such as pegmatite is formed when magma is crystallized around water and may also contain the beryl, tourmaline, and topaz.
There are two types of igneous rocks.
Volcanic or extrusive rock
This type of rock is formed on the surface of the earth. It requires air and seawater, which cools of the molten rock consistently to become glass-like or crystals. Volcanic rocks are grained most of the times with a glassy structure. Basalt is a type of extrusive rock which becomes finely grained due to its rapid cooling. It consists of tiny feldspar and pyroxene crystals. Some of the basalts can have gemstones in them. The usually found gemstones in basalt include corundum, zircon, and garnets. Kimberlite is another volcanic rock which is a major source of diamond.
Volcanic glass is cut into gemstones, and there is a variety of them. Obsidian is an amorphous mineraloid which has a hardness of 5.5 approx. There are different types of obsidians, including rainbow, reg mahogany, snowflake, midnight lace, silver sheen, and apache tears obsidian.
Plutonic or intrusive rock
This type of rock is forms and solidifies inside a preexisting rock. It takes time to cool down and forms plutonic rocks with larger crystals. The grains of intrusive rocks are much harder and coarse. Granite is one of the coarse-grained plutonic rock which contains quartz and feldspar. It usually carries mica or hornblende. In some of the cases, the granite experiences fractional crystallization.
Fractional crystallization is a process of slowing down the cooling which creates crystals of different minerals as they form at different temperatures. The pegmatite group minerals are the slowest to form, which also makes the veins to penetrate their surroundings.
Some of the minerals that are formed in ingenious rocks are
Diamond, Chrysoberyl, Garnet, Corundum, Feldspar, Quartz, Spinel, Topaz, Zircon, Tourmaline, and Peridot.
These minerals go through a long cycle of stages of igneous rock formation. It is also known as the magmatic cycle.
How can you find the gemstones?
There are many gemstones which have a large mining industry, such as Diamond. Diamond is obtained through the process of pit mining which uses heavy machinery and hydraulic equipment. The coloured gemstones, on the other hand, have a very different process. They are harder to obtain, and the process is much slower due to only a small amount of quality available. Since the quantity of gemstones is very scarce in the huge deposits of rocks, only independent miners are using the tools to mine these gems. It is still not a profitable choice for the mining industry to create mining projects for such gems. However, in the future, we can see new technologies and processes.