According to an old legend, having defeated the Gorgon Medusa, Perseus flew over the sea with her severed head. Where drops of blood fell into the water, red corals grew, which they called gorgonians. For a long time, scientists have debated whether corals belong to the class of plants or minerals. In fact, they are skeletal remains of organisms of the marine fauna and, like pearls, belong to organogenic minerals. Coral is one of the oldest jewelry materials and is incredibly popular today.
Instructions
Step 1
The coral industry has experienced ups and downs. By the 10th century AD, the North African Arabs had invented a way to extract coral. They crossed two beams four to five meters long, tied a heavy stone to them, and attached nets. Then the tackle was lowered to the seabed, corals were hooked, the branches of which broke, entangled in nets, and thus they were raised to the surface. Similar gear has been used for coral mining until recently. Today they are assembled using small submarines and robots.
Step 2
More than twenty types of coral are used by jewelers, the most valuable of which is the red noble coral. Corals have a hardness of 3-3.5 on the Mohs scale, so they lend themselves well to processing.
Step 3
Coral pre-processing is about identifying the best way to cut with a small amount of waste. This process also helps to hide natural defects (streaks, holes, lack of color saturation) and turn them into minor imperfections in the finished piece of jewelry.
Step 4
The coral branches are cut into pieces with circular saws. Then the individual pieces are ground and turned into beads. Others are cut with hand tools. Then they are polished and used to make various products: earrings, rings, bracelets. During the processing of raw materials, between fifty and seventy-five percent of the material is lost. This is why processed corals are expensive.
Step 5
There are various ways to upgrade poor quality corals. Colorless and pale corals paint over, giving them deep reds and pinks. This color will fade over time. White bamboo coral is converted into a rare black mineral using silver nitrate. And bleaching in hydrogen peroxide for 12-72 hours can give black corals a pleasant golden hue.
Step 6
Nowadays, the method of obtaining artificial corals is widely used. Their cost is ten times cheaper than natural ones. The main materials for the manufacture of imitation are plastic, porcelain, glass and coral shavings.
