The onyx or onyx (from the Greek onyx, nail) also known as marble onyx or calcareous onyx, is a mineral of group IV (oxides), according to Strunz’s classification, considered as a semi-precious stone. It is composed of silica (silicon oxide, SiO2).
Measurements: 9.5 cm high.
It has a volcanic origin, caused by the accumulation of volcanic gases. It is used mainly in jewelry and decorative items, due to the attractiveness of its greenish tones and the quality of its polish.
In Argentina this stone is found in the town of La Toma, province of San Luis, and in its surroundings. There it is maintained that its quarries are the only ones on the planet; and they are, but only green onyx. The world’s largest producer of onyx is Pakistan.
In Mexico the largest area in America is in La Laguna (Durango state).
