ETYMOLOGY: It comes from the greek "onux" meaning nail.

CRYSTAL SYSTEM: Rhombic.

PRINCIPLE OF FORMATION: Secondary.

CLASS MINERAL: Carbonates.

CHEMICAL FORMULA, MINERAL ELEMENTS: CaCO3.

HARDNESS: 3.5 - 4 on the Mohs scale.

FIELDS: Italy, Mexico, Brazil, Russia, South Africa, Pakistan.

MINERALOGY: The commercially known materials such as onyx (Onyx) are scientifically alabaster (or calcareous alabaster) formed by deposition of calcium carbonate-rich water bicarbonate, usually in cavities in the limestone massifs. The color of onyx is rarely uniform, so that the same site clear materials or even dark brown or white opaque (less appreciated variety) are alternated. Veins are very common or reddish brown spots, due to the presence of iron oxide. The varied color (beige, orange, brown, pink, red, green, blue, yellow) by impurities of different chemical composition.

MYTHOLOGY: It is a limestone compesta minerals such as calcite, not to be confused with chalcedony onyx. As early as the fifth millennium BC vases they were manufactured in Egypt with this stone. The age of the deposits of onyx usually recent (Pliocene and Quaternary), while the historical usage is antiguo.Ya Plinio remembers the material mined in quarries in Italy and Greece. In Italy, the most famous "onyx" is the Sicilian (Onice di Custonaci, for example), Lazio (Onyx Circeo, diverse color range, already known by the Etruscans), Piedmont (Onice di Busca), the Campania (onyx Gesualdo), as well as the so-called "stalagmite Carso" and the Lombards onyx from Bergamo. The Tyrolean Val Venosta onyx was used locally and Vienna. It is also noted the Tuscan variety ( "Onyx di Montalcino"), while the so-called "Alabaster of Volterra" is made of plaster.

PROPERTIES: Green minerals have a harmonizing and neutralizing effect. Green releases the feelings, increase the speed and responsiveness and arouse interest and enthusiasm. Green brings initiative and will to live, stimulates the sense and the ability of perception and draws our attention to the material world. Green minerals help deal with "poisons of the spirit", ie a negative considerations and promote a healthy optimism. Green is actually the color of hope.

CHAKRAS: Spleen and heart.

ZODIAC SIGN: Taurus.

USES: table tops, elegant counters, various decorative elements, fireplaces, wall coverings and columns backlit are some other applications besides their use in sculptures. Collection, meditation, jewelery.