The earth has been undergoing tremendous changes for over four and a half billion years to become the planet that we now know. That also applies to the fact that it has also taken that long to form some of the minerals and rocks that it has produced. Even though the earth is in perpetual change, evolution, and renewing, constantly making new rocks, this vision assists us by placing us in the right perspective about time and the formation of rocks and minerals. In view of that, let us consider: what rocks, crystals (gemstones) and minerals have in common and how do they differ?
Rocks, minerals and gemstones are all found beneath the vegetation and soil that cover the earth’s surface and as a result of different geological processes. Rocks and minerals make up the underlying crust of the earth. On the surface, the earth is covered by water, sand, soil and ice. In some places we can also observe exposed rocks, especially in the mountain ranges. Rocks are exposed as a result of rain, wind, erosion and volcanic eruptions that push them up to the exterior. A mineral is a naturally occurring compound or element found in the earth’s crust. Minerals are the most common material on earth. Unlike rocks, a mineral has the same chemical composition throughout and is made up of two or more chemicals. Minerals are not rocks. Rocks and crystals are minerals that have undergone different geological processes. Rocks are a combination of two or more minerals in different proportions. There are different types of rocks depending of how they are formed. Most rocks and minerals form deep in the crust as the contents from inside the magma escape through holes and crevices, the only exception is sedimentary rocks that develop from slow buildup of soil deposits. Crystals are minerals that form when liquid molecules bond through a process called crystallization. The molecules of crystals arrange themselves in regular and orderly patterns. With the exception of diamonds and peridot, crystals form within the earth’s crust. As a general rule, when people talk about crystals, they are usually referring to gemstones Crystal formation occurs when the liquid minerals from inside the earth cool and harden. Most mineral crystals take thousands of years to develop.
The tectonic plates make up the earth’s crust and they measure approximately three miles deep at the ocean floor and twenty-five miles deep under the continents. These plates glide over the mantle are in constant motion, friction and renewal from all sides. The magma is mostly molten rock, found below the surface of the earth’s crust in magma chambers. What escapes from the mantle, through the renewal process of the earth, becomes rocks and crystals.
