Emerald. Among the noble varieties of beryl, the emerald is the most valued. It is a stone with an intense green color, transparent to translucent.
The ingrowths commonly found in emeralds play a large role in distinguishing natural from synthetic emeralds and from other similar gemstones. The most characteristic are liquid inclusions, forming clusters called "gardens" (franc. garden). Sometimes they contain gas bubbles and small crystals. The larger droplets of liquid are most often found singly, small ones, on the other hand, create streaks of various shapes and "veils", running in different directions inside the crystal. Crystalline infixes come in a variety of forms. Cubes are common in Uralic emeralds, in Colombia, rhombohedrons prevail; especially in emeralds from the Muzo deposit, rhombohedral calcite infusions are common. In Ural emeralds, South African and Indian biotite plaques and amphibole needles are found (actinolite).
Research by an outstanding expert in precious stones B. W. Anderson showed, that emeralds from different deposits have different optical properties, especially the size of the refractive index and birefringence. Although these differences are slight, on their basis it is possible in many cases to determine where the stones come from.
Emeralds have been known for a long time and used for ornamental purposes. They are mentioned in the Bible, Theophrastus mentions them (372—287 r. p.n.e.) in his work on stones, Pliny the Elder writes a lot about them (23—70 r.) in his Historia Natura-Us. Emeralds, according to Pliny, they are most valued after diamonds and pearls. For the emerald has all the properties required of a gemstone, namely, it is hard and does not change under the influence of weather conditions.
Pliny enumerates 12 kinds of emeralds, discussing in detail the color differences and defects of some varieties. He considers the Scythian emeralds to be the noblest. They were probably emeralds from the Urals. He repeats after Theofrast, that the Babylonian ruler sent a giant as a gift to the Pharaoh of Egypt: emerald in length 4 and width 3 cubitus (1 cubitus = 33 cm). Even larger emeralds were allegedly in the temple of Jupiter, and according to another ancient author, an emerald of a length was stored in the Egyptian labyrinth 9 cubitus.
Emerald is a type of beryl, which was found only before 150 patches. Previously, emerald and beryl were considered different minerals, although Pliny had already pointed out, that beryls have the same or at least similar properties to emeralds. Repeating the news of the emerald pillar after Theophrastus, which was allegedly located in Tire in the Temple of Hercules, adds from himself, that it was probably a pseudo-emerald. Undoubtedly, the descriptions of giant emeralds made reference to beryl, which are sometimes in the form of very large crystals. According to Pliny, these beryls came from India. Chinese monk and Fa-Hien pilgrim, which in the years 414-399 BC. wandered India and Ceylon, he saw emeralds adorning Buddhist temples.
Arabic scholar Ibn Alfagih (about 900 r.) mentions Egypt as the home of emeralds. There is a mention in the preserved Egyptian papyrus, that in the 16th century. p.n.e. There were emerald mines in Upper Egypt east of Aswan, near the shore of the Red Sea, known as the Cleopatra Mines. During Sesostris, emeralds were mined there both from surface pits, as well as from the depths of the earth. W 1650 r. p.n.e. however, these mines were considered exhausted, therefore further mining works were abandoned. Later mining works were carried out there by the Romans and Turks; they were abandoned in the mid-18th century. These mines were rediscovered at the beginning of the 19th century.
The Romans probably also mined emeralds in the Salzburg Alps, in today's Habachtal valley. W XIX w. the Venetians became interested in these mines, who were to send emeralds to the courts of Italian princes. W 1689 r. these mines were visited by Nils Stensen, professor from Florence, meritorious in the field of crystallography and geology. Attempts to rebuild these mines were resumed in the mid-19th century., their efficiency, however, did not increase the costs of mining works. For some time, emeralds from the Habachtal deposit were operated by the English company Emerald Mines Ltd from London, which, however, was resolved in 1886 r. The attempts to resume operation in the interwar period also gave little results. After the Second World War, a Pole started to rebuild these mines, Eng. Hubicki.