Description
Onyx is a mineral and a variety of quartz, more specifically a variant of chalcedony. Onyxes are two-colored nesosilicates, with the colors interwoven as layers or bands. Onyx is related to agate, a four-colored quartz variety. There are several types of onyx, with the base name onyx normally used to indicate a mineral with white and black layers. We also know sardonyx with white and reddish-brown (the color called sard) layers, and carnelian or carnelian onyx (fiery red and white layers). Onyx is found in Brazil, Madagascar, Mexico, Uruguay, the United States, and Pakistan. Onyx is a popular mineral for use as a gemstone in rings and pendants. Black onyx is particularly popular for jewelry worn at funerals, due to the beautiful contrast of the deep black and pearly white that characterizes this stone. Onyxes are usually cabochon-cut—that is, rounded and polished, not faceted like diamonds. Onyxes are also sometimes cut into beads. Both forms preserve the natural, flowing whiteness of the colored material and avoid sharp edges. Furthermore, onyx is used to make seal stones and cameos, where they are cut so that the bands contrast with the base material. Onyxes are also used to cleave other stones. In ancient times, carnelian was mined in North Africa as an ornamental stone. During the imperial period, onyxes were primarily used for gemstone making; rings with such stones were regularly found in the western provinces. In the late Roman period, carnelian beads were also found in the eastern provinces. Above the Alps, carnelian beads were found only occasionally, such as in Pfyn and Switzerland. References to the onyx appear in several places in the Old Testament of the Bible, the first in Genesis 2, verse 12. According to Rabbi Bahya ben Asher, the word "shoham" in Exodus 28:20 means onyx. According to him, onyx was also the stone on the ephod that represented the tribe of Joseph. In addition, the shoulders of the ephod were also adorned with two such "shoham" stones. The onyx has an esoteric history almost as long as its secular history. In the Middle Ages, the onyx was already considered a "stone of misfortune," a symbol of mourning and misery. Other sources state that it was also a healing stone, with a positive effect on the skin, hair, and nails. Within the zodiac, onyx is associated with Capricorn and Saturn. Onyx is also said to have a beneficial effect against nausea, weather sensitivity, and gastrointestinal complaints.
Citrine, or lemon quartz, is the lemon-yellow, translucent variety of the mineral quartz (SiO2). Properties: Like other varieties of quartz, translucent citrine is a nesosilicate. The yellow color is caused by trace elements, primarily divalent and trivalent iron. Citrine has a trigonal crystal system, and its hardness is 7. Name: The name citrine is derived from citrus (due to its yellow color). Depending on its color, this quartz variety was also formerly called Madeira topaz, golden topaz, or Bahía topaz, entirely incorrectly, as topaz is a completely different mineral. This was likely done to suggest greater value. Occurrence: The main sources of citrine are Brazil, Madagascar, and the former Soviet Union. Amethyst is often burned and sold as citrine. This can be recognized by its brown to black tips. Citrine is more valuable than amethyst.
