- Chalcedony (/kælˈsɛdəni/ kal-SED-ə-nee, or /ˈkælsəˌdoʊni/ KAL-sə-doh-nee) is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony’s standard chemical structure (based on the chemical structure of quartz) is SiO2 (silicon dioxide).
- Antares (stars.astro.illinois.edu)
ANTARES (Alpha Scorpii). A brilliant jewel set within the Milky Way, Antares guides us to one of the great constellations of the sky, the Zodiac’s Scorpius (or Scorpio), the celestial scorpion, one of the few constellations that actually looks like what it represents.