Categories of Gemstones

There are many different types of gemstones, and knowing the different categories can help a collector or enthusiast expand his repertoire greatly. Some precious gemstones are so unique in chemical composition and crystalline structure that they fall into their own categories, while others can be collectively lumped into one. Here are the major types of precious and semi precious gemstones:

Diamond - diamond is it's own type of gemstone, and is well known for being the hardest naturally occurring substance known to man. Diamonds are primarily high-carbon crystals that were fused under extremes of pressure and heat.

Diamonds themselves aren't especially rare, with thousands being mined throughout the world every year; however, large diamonds of high quality are extremely rare, and it is these which are well known for setting the standards of diamond gemstones as the world's most precious stone.

Corundum - this is the second hardest type of gemstone, and is primarily defined as being composed of aluminum oxide and various trace minerals. The trace minerals create different types of corundum, and perhaps the two most well known examples of this type of stone are rubies and sapphires. Rough corundum isn't used as a gemstone, but is used as an industrial strength abrasive element due to it's tough nature.

Chrysoberyl - this is the third hardest gemstone, and while it uses aluminum oxide as a base element like corundums, it has high quantities of beryllium mixed in with it. Appearance wise, chrysoberyls often come in a green to yellow shade, though their appearance is best known for having the tendency to actually change color somewhat under different types of lighting. Cat's eye and alexandrite are two common chrysoberyls used in jewelry.

Quartz - this is actually one of the most common types of mineral in the world and comes in a wide variety of colors. It's main tendency is to form in hexagonal shapes and it makes an excellent prism if unflawed.

The main reason quartz can still be categorized as a valuable gemstone is that, while it IS easy to find quartz stones, finding a large, perfect, and unflawed quartz crystal of jewelry quality is extremely rare. Some examples of quartz gems commonly used in jewelry are onyx, amethysts, citrines, and carnelians.

Beryl - this is a stone well known for it's beauty and has elements in common with both chrysoberyl and quartz. It's basic chemical composition is similar to chrysoberyl, with beryllium and aluminum prevalent but mixed in with other trace elements. It's basic crystalline structure, on the other hand, is closer to quartz, being hexagonal in nature.

At it's simplest, beryl is actually transparent, while it's other colored variants include emeralds and aquamarines. It can come in yellow and red shades as well, and these are referred to as "red" or "yellow" emeralds.

Jade - this is one type of gemstone originally lumped into the same category as beryl. The main reasons for this are because both can be mined in similar places and they possess similar textures, opacity, and appearance (just different colors).

Later on, chemical analysis showed that the elements which made up the different forms of precious jade, namely nephrite and jadeite, were different from beryl completely, thus earning jade it's own category among gemstone collectors. Jade based stones are often composed of calcium and magnesium elements.

Feldspar - this is a unique type of gemstone whose base material is tectonic in nature. It is often found in areas of high geographic instability like earthquake faults and volcanic chains. Feldspar's basic chemical composition is made up of very common elements found deep inside the earth's crust.

What makes it valuable as a gemstone is the same factor that makes a diamond much more valuable than a lump of coal that would normally contain the same elements as diamond. That is, with sufficient heat and pressure applied, the tectonic elements fuse together to make a rare red gemstone known as feldspar.

Organic Gemstones - the most famous examples of this are pearls and amber. Basically, organic gemstones are ones which occur naturally in organic sources as opposed to mineral sources. Pearls are formed from oysters, while amber is a yellow stone formed from fossilized tree sap. While not gemstones per se, organic gemstones are still used heavily in jewelry so are included in this list.

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The Gemstone Mining and Making Process

So you're wondering how exactly your jewelry came to be. Well, that's a normal question any jewelry enthusiast would ask. You do question how these gems are placed into metal. You also question where exactly these gems came from.

There are gemstone mines everywhere around the world. The most popular are in Brazil, Canada, Mexico, Uruguay and Africa. There are also mines in Europe and the United States, depending on what kind of gem stone you are looking for.

Amethyst

Amethyst is the most valuable kind of quartz. It is found everywhere around the world. For this very reason, it is one of the most affordable. The quality of amethyst is quite unique, depending on where it was obtained. Amethyst that are found in the United States are larger compared to those found in Africa. However, the latter has higher saturation when it comes to their colors.

Amethysts with the highest saturation are those found in Australia. There are also amethyst found in Brazil are usually large and have hues and cuts.

Emerald

Emeralds are mostly found in Mexico. Two main sources are the mines in Guerrero and Vera Cruz. Emeralds found there have the tendency to have lighter shades and are clearer than those found in other countries. The stones have lighter hues and the crystals are phantomed with a transparent interior and a saturated exterior.

Emeralds that are found in Guerrero are saturated dark green. They have a visible termination of their interior color saturation and exterior transparency. The highly saturated emeralds are the most elegant.

Sapphire

The most notable source of Sapphires are those found in Brazil from Minas Gerais, Bahia, Maraba and Rio Grande do Sul. Among those containing the best sapphires are the large pockets that are formed by the volcanic material.

The sapphires that are produced here vary in their color saturation which ranging from pale up to medium blue. Those that are navy blue are the sapphires that have the highest saturation.

Diamond

Africa is known to be a producer of diamonds, thus the inspiration of the recently released blood diamond. There are diamond deposits in Zambia and Namibia. The diamonds found in Africa can be as large as an egg and are outstandingly clear.

Jade

The United States has various gems. In Maine, North Carolina, Pennsylvania, Montana and Colorado, the most popular stone is the Jade. The color depends from the medium saturation. It may be smoky or translucent, depending on where it was obtained.

Jade from Maine and North Carolina are usually dark while those found in Montana or Colorado have a green tint.

Now, the next question, how are the jewelry is made. Diamonds, emeralds, sapphires, amethysts, and jade are only a handful of precious gemstones out there. Some of them are very valuable because of their rare appearance.

How are these gemstones formed? Well, they are formed underneath the Earth. The process involves vary in each gem stone. The stones react with the minerals, specifically water. This is how they are dissolved. When the solution evaporates and cools down, these minerals are formed.

The water then mixes with the silica-rich rocks like sandstone. This produces the gemstones like amethyst, opals, agates, sapphires, jade and topaz to name a few. When the copper-rich rocks mix with the water, it bears the minerals like turquoise, malachite and azurite.

Emeralds and tourmalines are formed from rain water or the water that is from cooling bodies like magma that is mixed with the minerals and crystallized in cavities or open cracks. These spaces are filled with minerals which create the hydrothermal deposits needed in the formation of these gem stones.

There are also gemstones that are formed directly from the mantle. They consist up to 70% of Earths total mass. They are usually made up of magnesium, silicon, iron, oxygen, silicate and aluminum compounds. The upper layer of the Earths mantle has a volume of the olivine which is quite common in the whole procedure.

Whenever you hear the word metamorphic it means the change of form of these rocks. Metamorphic gems are garnet, emerald, ruby, aquamarine, sapphire, onyx and zircon. They are formed over a long period of time because they wait for the rocks to be altered with such pressure and intense heat in order to interact with the other solutions.

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