Gems - as their name suggests - they stand out from other minerals with their beauty, durability and rarity. They are of various colors, usually transparent and highly shiny. The colors of gemstones make up the beauty of gemstones, transparency and purity, vivid shine and fire.
The diamond is the most valued, admittedly mostly colorless, but of unparalleled brightness and fire. Emeralds, rubies and sapphires are beautiful, deep colors, but the shine is much weaker than diamonds. Opals attract with their play of colors, and the opaque turquoise - a kind of bluish color. Transparent stones are especially appreciated, with delicate and subtle shades. To bring out the full glow of the crystals, grinding is used, i.e.. artificial production of numerous walls reflecting and refracting light rays on the surface of the stone.
Durability is a decisive factor for the value of gemstones, thanks to which they do not change for a long time. They are not only resistant to damaging chemical effects, but they are very hard and will not be scratched by surrounding objects or airborne dust particles. Diamond has the highest hardness of all minerals, which - among other properties - decided, that it is considered the most precious gemstone. Ruby and sapphire have a hardness similar to that of a diamond, chryzoberyl i topaz, slightly smaller - emerald and aquamarine, zircon and pomegranates.
For centuries, apart from the diamond, among the most valuable stones, sometimes called the king of precious stones, emeralds, rubies and sapphires. They were and are in great demand, reaching the highest prices compared to other stones, sometimes referred to as semi-precious stones. The traditional division of stones into precious and semi-precious stones is not strict. An example is opal which is usually considered a semi-precious stone, as well as the different varieties of quartz and chalcedony. Some varieties of opal, however, characterized by a beautiful play of colors, are classified as precious stones. At international jewelers' conventions, efforts are being made to remove this division, the main basis of which is the price of stones, nevertheless, the name semiprecious stones continues.
The author of a very extensive monograph of precious stones, M.. Bauer (III wyd. prepared by K. Locksmiths, 1932) included among the precious stones: diament, korund (rubin, sapphire), chryzoberyl, spinel, topaz. beryl (emerald, akwamaryn). euklaz, zirconium (hyenant), tourmaline, oliwin, spodumen (hiddenit, kunzyt),. noble opal and turquoise. They were classified as semi-precious stones by him: prehnit, cordierite (returned), opal, turquoise, sodality, lazuryt (lapis lazuli), grenades (pirop, almandyn, spessartyn, hessonit, demantoid, uwarowit), Andalusian, sillimanit, quartz (Mountain crystal, lemons, smoky quartz, morion, ametyst i in.), amfibol (nephrite), pirox (jadeit), scalenia (adulatur, moon stone, microcline, labrador i in.), wezuwian, piryt, chalkopyrite,. markasyt, hematyt, serpentyn, agalmatolit, malachit, dioptaz, smitsonite, chrysokola, obsydian, moldavite, amber, gagat.