Gemstones are judged for their hardness and rarity. In the majority of cases, they are more expensive than semi-precious stones. To date, there are only 4 types of so-called precious stones.
4 Precious stones in the world
Diamond is renowned for its exceptional physical qualities, most of which come from the strong covalent bond between its atoms. In particular, it has the highest hardness and thermal conductivity of any material.
Most natural diamonds are between 1 and 3.5 billion years old. The vast majority formed at depths of 150 to 250 kilometers in the Earth’s mantle, although a few have been discovered at depths between 400 and 800 kilometers.
Many people expect a diamond to be unbreakable. This is not the case according to OR du Monde, a diamond specialist. The crystal structure of a diamond has “hard” and “soft” directions. A blow of sufficient force, in a specific direction, can split, chip, or even shatter a diamond. The World’s Most Precious Stones
Emerald is one of the most fascinating and beautiful gemstones in this selection. Its crystals are usually small, with an average length of 2 to 5 cm and a width of 1 to 1.5 cm. Larger crystals are generally semi-transparent to opaque.
The most sought after color is slightly bluish green with a medium dark tone and strong saturation. Clarity is important, but inclusions are more tolerated in this variety than with other types of gemstones. Premium, unenhanced stones (with certification) can fetch up to 50% more in price than treated stones of the same size, color, and clarity. List of Gemstones Types, Names, Colors, Precious, and Semi-precious
Ruby is the red variety of the mineral corundum, one of the hardest minerals on Earth, of which sapphire is also a variety. Corundum is the mineral form of alumina that crystallizes in the hexagonal system.
The red color of the ruby results from a small mixture of chromic oxide. Only red corundum is so called ruby, all other colors being classified as sapphires. The most popular hue is blood red or crimson, known in the trade as blood red.
The quality of a ruby is determined by its color, cut and clarity, which together with weight (calculated in carats) affect its value. The brightest and most valuable shade of red, called blood red or pigeon’s blood, is far superior to other rubies of similar quality. What makes precious stones special?
Sapphire is also a variety of the mineral Corundum and represents all colors except red Corundum, which is Ruby. Its physical and chemical properties are practically similar to the properties of ruby. Blue is the primary color of sapphire while this gemstone is also found in colors like green, orange, pink, gray, colorless, black, brown, and purple. What is Sapphire (Communication Stone)? Health Benefits of Sapphire Stone
The sapphire gemstone symbolizes harmony, friendship, and loyalty.
Sapphire is the most valuable blue gemstone. It is a highly sought after gemstone due to its color, hardness, durability, and luster. The value of this gemstone depends on its size, color, & transparency. Top quality sapphires are extremely rare in any gemstone mine in the world.
So much for the 4 gemstones, you now know. These stones can be worth several million euros, in 2017 a diamond was sold for a total of 34 million dollars. Color Of Precious Stones, Semi-precious Stones & Jewellery