ETYMOLOGY: The name is because it is made up SARDO = red-brown, ONYX = (agate ónix-).
CRYSTAL SYSTEM: Trigonal.
PRINCIPLE OF FORMATION: Primary / Secondary.
CLASS MINERAL: Oxides, quartz group.
CHEMICAL FORMULA, MINERAL ELEMENTS: SiO2 + C (Fe, O, OH).
HARDNESS: 7 on the Mohs scale.
FIELDS: Brazil, India, Russia, Asia Minor.
MINERALOGY: A variety of agate, the most important variety of chalcedony. It is a type of onyx characterized by two or more layers of milky chalcedony and transparent red ruby, although sometimes strong color coat is golden or brown. The sardonyx is formed by the inclusion of iron and manganese, it originates hydrothermally hollow cavities in rocks.
MYTHOLOGY: The name is mentioned once in the Bible, in Revelation 21: 2, 19, 20, which states that the fifth foundation stone of the "holy city, New Jerusalem," is a sardonyx. The sardonyx was highly valued in Rome, especially for seals, because it was said that never stick to the wax. The Roman general Publius Cornelius Scipio was known for wearing large amounts of sardonyx.
PROPERTIES: It is said that the sardonyx provides strength and protection, is a stone that attracts friends and good luck, mentally improves the perception and assimilation capacity, gives us stability, confidence in ourselves and in others, helps us to overcome pains and brings joy to pass on to others, overcoming power birthstone strengthens the will, makes us kind and generous.
ZODIAC SIGN: Virgo.
USES: Jewellery, meditation, collection, ornamental stone.