"Pearls are the tears of the sea and diamonds sparkles of the stars" this was believed by the Indians hundreds of years ago. In that time women adorned themselves with own made jewels to show their fertility and status. That we still wear our wedding ring on the left ring-finger comes from the belief of the ancient Egyptians, they believed, that the love-vein goes straight from the heart to the ring-finger. Precious stones, valuable gifts of nature, are as we look closer minerals, who characterize themselves by particular characteristics such as colour, transparent, lustre, hardness and play of colours or special encirclements. The formation of precious stones is very close connected with the origin of solid rock. Geology divides stones into categories of origin
• Magma stones, which rise as a glowing flow from the depth and then harden in the earth'' s crust (diamonds)
• Sediment stones, caused by stone layers and water, wind and ice ( almost all kinds of precious stones)
• Metamorph stones, caused from other stones by heat- or pressure changes (rubies)
In all these stones we find precious stones, which mostly are formed to crystals. Among the oldest precious stones, who were worn by humans as jewels or made into article of use or object of art belong the emeralds and the pearls. The weight, the mass is indicated by carat (ct). This name comes from the Arabian word kirat, the meaning for the seed of the Johannesbreadtree. The weight of real pearls is indicated in Grain and the mass of cultivated pearls is indicated in carat. The valuation of precious stones depends on colour, clarity, cut and size. For diamonds is the magnifying quality the most important characteristic for the valuation. For precious colour stones the intensity of the colour is the most important characteristic. The cut has to be perfect to bring out the special characteristics of the precious stones. The stories of the discovery of the precious stones are full of adventures. The South African diamond resources were discovered in 1867, when children found sparkling stones along the banks of the Oranjerivier when they were playing there. About 1830 there was a hurricane in the Urals who destroyed a lot of trees in that area. When the local farmers started digging out the roots of the trees they found beautiful green stones, emeralds. In Brasil gold-seekers used sparkling stones as chips for their games, not knowing it were diamonds, till they were identified as such in 1721.