The 12 types of gemstones (and their characteristics) - medical - 2023



$ 65,000 per gram. This is the current price of the diamond on the market, one of the precious stones par excellence. And it is that these minerals, formed by natural geological processes, are so rare and valuable for jewelry making that their prices skyrocket. Gemstones are excellence made rock.

And of the more than 4,000 types of minerals (inorganic solids of geological origin) known, only about 300 species meet the criteria to be considered as gem: beauty, durability and scarcity. When a rock meets these three conditions, it makes it a precious object for art or for the world of jewelry.

And although there are only four precious stones as such (diamond, emerald, ruby ​​and sapphire), there is also a much broader group of gems known as semi-precious stones, which although they do not enjoy the fame and exclusivity of the previous ones, they are absolutely wonderful rocks.

So, in today's article, we will embark on an exciting journey to discover the main types of precious and semi-precious stones, classified according to their properties and their origin. Ready to see how far beauty goes in the world of Geology? Let's go there.

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How are gems classified?

A gem is all that mineral, that is, inorganic substance of geological origin, in which the atoms of the elements form structures that are stable enough at a chemical and physical level to give rise to a rock that develops geometric patterns to give rise to a glass that meets three criteria: beauty, durability and scarcity.

When a rock meets these three conditions, we speak of gems. And as we have said, of the 4,000 known mineral species, only 300 are gems, which They are classified into two large groups: precious stones and semi-precious stones. Let's see the classification within each of them.

1. Precious stones

Gemstones as such are the most perfect gems and that best meet the three criteria that we have seen. They are the most beautiful, durable and rare rocks in the world. All this makes them luxuries available to very few and their prices are, to say the least, exorbitant. As we have mentioned, there are only (although obviously it is an arbitrary criterion) four precious stones:

1.1. Diamond

Diamond is the gemstone par excellence. It is a rock that consists of the hardest mineral on Earth and the only gem of all that is made up exclusively of a single element: carbon. It is a mineral made up of carbon atoms arranged in a perfect crystalline structure.

For its formation, very high pressures are required that are only reached about 200,000 meters below the earth's surface. And after this process, we must wait for the movements of the tectonic plates to take them to more external parts in order to obtain them. Do not forget that the deepest we have been able to excavate is 12,000 meters. So, to have diamonds, we depend on tectonic movements.

It is believed that the diamonds we have today were formed during a process that could take up to 3.3 billion years. Or what is the same, three quarters of the age of our planet. And its beauty properties in jewelry, its durability (it is the hardest mineral that exists) and its low abundance make its value about $ 65,000 per gram.

In other words, if we wanted a kilogram of pure diamond, we would have to prepare to shell out $ 65 million. However, the largest diamond ever discovered was obtained in 1905, in South Africa. The one baptized as the South Star, was an overwhelming 621 gram diamond. The most precious stone of all precious stones.

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1.2. Emerald

Emerald is one of the most beautiful gemstones that exist. From greek Smaragdos, which means "green stone", emerald is a cyclosilicate mineral composed of beryllium, aluminum, chromium and Vanadium, the chemical element that makes it have its characteristic and amazing deep green color.

It should be noted that much of its value lies in transparency. And it is that although the most opaque emeralds are common, we speak of precious stone when the gem is as transparent as possible, free of internal imperfections. This variety, which is known as the "emerald garden", is the one that really has value. Colombia is the country where more deposits of this gem have been found, which, traditionally, has been associated with miraculous virtues. In fact, for alchemists it was the stone of Venus.

1.3. Ruby

The third of the precious stones. Ruby is the red variety of corundum, one of the hardest minerals that exists. As a corundum mineral, its structure is based on aluminum oxide together with metals such as iron and chromium that give it its reddish color. In fact, "ruby" comes from Latin ruber, which means "red."

It should be noted that, although there are deposits in many countries (Brazil, Colombia, Russia, China, Burma, Sri Lanka, India, Madagascar, Thailand and even the United States) rubies obtained from the peninsula of Malaysia and Tanzania are so precious that their value can be as high as that of diamond.

1.4. Sapphire

Sapphire is another variety of corundum. In fact, the only difference from ruby ​​is at the concept level. And it is that although we speak of ruby ​​when it comes to red gems, the sapphire is all that corundum gem of any other color, including pink. However, we generally speak of sapphire when the color is blue, but it can actually also be green, orange, purple, brown, and even black.

In the case of blue sapphire, the most precious and recognized as sapphire itself, in addition to the aluminum oxide of corundum we have metals such as iron and titanium (in ruby, it was iron and chromium), a mixture that gives it its characteristic blue color. The word "sapphire" comes from the Hebrew Safir, which means "neat." By way of curiosity, it is known that Antarctica is rich in this precious gemBut in order not to upset its (already) delicate balance, its exploitation is extremely limited.

2. Semi-precious stones

Semi-precious stones are all those gems that, although they are not as beautiful, durable, resistant and rare as precious stones as such, they are still highly valued minerals in the world of art and jewelry. They are rocks that stand out for their appearance and, in this case, there are about 300 different species. As not all of them can be presented, the most common is to classify them according to their color.

2.1. Black stones

Black semi-precious stones are extremely beautiful gems, as their color makes them look like something from another planet. Examples of gems in which the color black predominates are jade, melanite, onyx, agate, jet or rutilated quartz.

2.2. Red stones

In addition to ruby, there are semi-precious stones that have, in the color red, their main exponent to be considered as gems. They stand out, to give some examples, the zircon, the coral, the garnet, the andesine, the cornelian, the opal of fire or the spinel.

2.3. Pink stones

Pink is a rare color in nature. So the gems in which this color predominates, being scarce, are also very precious and valuable. Examples of pink stones are topaz, kunzite, Malaysian garnet, morganite or rose quartz.

2.4. Yellow stones

Yellow stones may not be so precious in the world of jewelry, but visually they are, of course, wonderful. The gems where yellowish tones predominate are, for example, citrine, lemon quartz, tourmaline, spodumene and sphene.

2.5. Green stones

Beyond the well-known (and already analyzed) emerald, there are other semi-precious stones in which the showy green color predominates.. The most precious and valuable green gems are alexandrite, amazonite, malachite, variscite, enstatite, aventurine, chrysoberyl, apatite, ammolite, turquoise, peridot, jadeite or larimar, to name a few. examples.

2.6. Blue stones

Blue is, as a rule, a rare color in nature. But in addition to sapphire, there are other semi-precious stones in which this color predominates and which are authentic geological wonders. To give some examples, we have lolita, topaz, moonstone, lapis lazuli, hawk eye, chrysocolla, aquamarine and fluorite, in addition to many of those that we have seen in green gems but that can also adopt bluish tones.

2.7. Violet stones

The semi-precious stones of violet color are also very precious and valuable. Examples of violet gems are, for example, kunzite, chalcedony, amethyst, tanzanite, sodalite or lepidolite, in addition to other stones that we have seen before and that can adopt a coloration of this type.

2.8. White stones

The absence of color can also be something that attracts attention. And proof of this are not only the diamond, but also these semi-precious stones. White gems, such as howlite and some varieties of quartz and moonstone, are highly valued in the world of jewelry and art in general.