According to the international gemstone classification, there are only four stones that we can call precious. Among them, Diamond, Sapphire, Ruby, and Emerald. All the rest is semi precious stones. Over time, the list of gemstones has been changed numerous times. For example, Opal previously was on this list. But later, people noted the "negative" features of this stone. As a result, it has gotten out of the charts.
Peridot (Chrysolite) was also considered precious. But when the miners found its vast deposits, it also turned semi precious. Our ancestors called all the red stones Ruby. But afterward, the scientists separated these varieties. Earlier, the ancients believed that Topaz is valuable. But many researchers doubt, whether or not it was in fact Topaz. Today we adhere the international standards. Therefore, we count only four stones as genuine precious.
The List of Precious Stones of The First Grade
Diamond is the most famous precious stone that possesses the highest hardness and brilliance. However, it is not, in fact, the most expensive despite the prevailing opinion. Nonetheless, this gemstone has a rich history, which is surrounded by many myths and legends. This gem is the birthstone appropriate for April. Read more about Diamond
Emerald is most expensive among all the gems if it contains no flaw. The Spanish conquerors discovered this stone in Peru. However, the Egyptians also mentioned it in their treatises. But our ancestors called all the green stones "Emerald." This gem symbolizes the Birthstone for May. Read more about Emerald
Being an expensive variety of Corundum, Ruby ranks almost equal to Emerald. Though chemically it is almost the same precious stone as Sapphire. Ruby of the so-called "pigeon's blood" color is quite rare and esteems higher than a regular Diamond. Ruby considered a birthstone appropriate for July. Read more about Ruby
Sapphire is a deep-blue Ruby, while its color is the most valuable quality of this gem. This gem is next to Diamond in hardness (9/10). It is equal to Ruby in other qualities excepting just a color. It is the most magical and sacred stone of the ancients. Today this precious stone correlates with September Birthstone. Read more about Sapphire
We may call Natural Pearls a precious stone. However, a Pearl, being a product of wildlife, is not a gemstone in fact. Nonetheless, the natural Pearls are precious, despite this fact, though it could be classified separately. Pearls possess a rich history as Diamond and other precious stones. Pearl is a Birthstone for September, as well. Read more about natural Pearls
Precious Stones of The Second Grade
There are various gems that we may classify as precious due to their utmost rarity. Among them, it's worth noting Alexandrite. Despite the fact that the official charts don't contain this gem in the list, we tend to classify it as precious as well.
Natural Alexandrite is a relatively rare gem primarily of Russian origin. This gem owes its name to Russian Tsar Alexander II. Its deposits locate in Uralian emerald mines that were found in 1883 by one Finnish mineralogist. Its deposits are limited and exhausted if to compare the Russian and Sri Lankan mines. However, there are some new mines in Brazil, South Africa, and Madagascar, which probably might produce some pretty good specimens. Read more about Alexandrite