Features of gemstones with particular emphasis on diamonds

Diamonds are one of the few gemstones that almost everyone knows. They arouse admiration and desire. However, they are not the only ones. These natural wonders also include, among others, sapphire, ruby and emerald, the so-called great four gemstones. This group shares similar physical features, i.e. durability and hardness, rarity and aesthetic values. In this study, we will have a closer look at these stones, with particular emphasis on diamonds.

Diamonds are unique gemstones

Diamond is made of carbon atoms and is the hardest mineral that occurs in nature. The first diamonds were created billions of years ago - inside the Earth, as a result of high pressure and high temperature. They differ in many respects, which is why it is so difficult to find two identical stones.

The ancient Greeks valued indestructible stones and believed they had mystical powers. Diamonds have always symbolized power, wealth and high social status. It was diamonds that decorated the insignia and jewellery of rulers, members of royal families and nobles.

Diamonds are a luxury good. Therefore, at times of turmoil on the financial markets and investors looking for safe haven - they do not gain as much as gold. However, precisely because of their constant value, tangibility and the possibility of mobility - diamonds can be treated as a luxurious but safe haven.

Features of gemstones

Precious gemstones include diamond, sapphire, ruby and emerald. The remaining stones belong to the group of semi-precious gemstones. It is the most popular division dating back to antiquity. However, it may suggest that gemstones are more valuable (more expensive) than semi-precious stones, which is not always true. Accordingly, this approach is now being abandoned.

Gemmologists currently classify precious stones as gemstones by the following features:

I. Durability and hardness (at least 7 on the Mohs scale).

We use the Mohs scale to evaluate the hardness of the mineral. Hardness should be understood as the resistance of a given material to scratching by another mineral or object. The Mohs hardness scale is 10 degrees: 1 is the softest, easiest to scratch, and 10 is the hardest.

Mohs scale (softest to hardest):

1. Talc (very susceptible to scratching, you can even do it with your fingernail)

2. Gypsum (prone to scratching even with a fingernail)

3. Calcite (can be scratched with copper wire)

4. Fluorite (prone to knife scratching)

5. Apatite (difficult to scratch with a knife)

6. Orthoclase (can be scratched with a metal tool)

7. Quartz (can scratch glass)

8. Topaz (will scratch glass without any problems)

9. Corundum (cuts glass)

10. Diamond (can only be scratched with another diamond)

Graph 1. Mohs hardness scale 

Source: https://www.gemsociety.org/article/select-gems-ordered-mohs-hardness/

II. Rarity of occurance.

Diamonds are quite common. Last year, 113 million carats were extracted. However, most of the extraction (80%) are diamonds which are mainly used industrially. They are of poor quality, most often very small stones weighing a few hundredths of a carat. The diamonds used in jewellery are the rarest, including those in fancy colours. Russia's Alrosa, one of the largest mining companies, estimates that fancy-coloured diamonds account for 0.01% of total mining.

III. Aesthetic qualities: brilliance, clarity and colour saturation or complete colourlessness.

The third and last condition for including gemstones in the group is their aesthetic value. Precious stones, after cutting and polishing, are characterized by good shine, clarity and colour saturation. This allows these stones to sparkle beautifully and delight us with their beauty.

Breakdown of diamonds – according to their use

Diamonds can be classified according to the way they are used. We distinguish:

Industrial diamonds, which account for approximately 40% of the total diamond market.

Diamonds for jewellery use, of the highest quality, account for 20% of the extraction and are intended for the luxury jewellery market

The remaining 40% of diamonds (depending on price and demand) are split between the needs of a specialized industry and the market for lower quality jewellery. As a rule, most of these stones go industrial use. (page 8, edu part II)

Chart 1. Breakdown of the use of diamonds in the world

Diamonds in industry

Diamonds are resistant to very high temperatures, conduct heat well and are an insulator of electricity. The hardness of a diamond is used in abrasive machines and drills. They are used in specialized medical and industrial devices.

About 40% of diamonds mined annually go to some other than jewellery industry. They are mostly very small stones of very poor quality, unsuitable for use in the jewellery business.

Diamonds in jewellery

Gem quality diamonds can be divided into commercial and investment diamonds. Unique stones of the highest quality can be used as investment assets. These are very rare stones, the supply of which is very limited. This applies to stones of the highest clarity, which are perfectly colourless and have a large mass (weight). Such diamonds do not occur very often, so their prices are very high, and the stone itself holds the value very well.

Coloured stones are less available but more desirable. Their prices are much higher than these of colourless diamonds. Coloured diamonds are extremely rare and buyers are willing to pay many times more for them than for colourless stones.

Commercial diamonds used for the production of jewellery do not have to have such high parameters as investment diamonds. Jewellery uses diamonds with a lower weight or with impurities invisible to the naked eye. 

Diamond, sapphire, ruby and emerald - the great four of gemstones

Gemstones share several similar physical characteristics. Each of them must have a hardness of min. 7 on the Mohs scale. In order to classify a mineral as a precious stone, it must also be rare and have appropriate aesthetic qualities. Only stones with adequate clarity, visual effects and colour saturation can be classified as gemstones. This classification is met by diamonds, sapphires, rubies and emeralds, the so-called the great four gemstones. These are unique jewels that decorate the most beautiful jewellery pieces.

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Fancy Colour Diamonds

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