Carnelian

Hardness: 6.5-7 on Mohs scale. Color: Translucent red, orange, reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Trigonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Carnelian is a variety of chalcedony, which is a cryptocrystalline form of silica. It forms from the precipitation of silica-rich fluids in volcanic and sedimentary rocks. The red to orange color is due to the presence of iron oxides (hematite). Its geological age can vary widely depending on the formation environment, often found in relatively young volcanic deposits or weathered sedimentary beds.

Carnelian has been used for thousands of years in jewelry (beads, cabochons, carvings) and ornamental objects due to its attractive color and ease of polishing. It was also used for seals and signet rings in ancient times due to wax not sticking to it. Today, it is popular in lapidary arts, decorative items, and as a collector's stone.

Carnelian was highly prized in ancient civilizations like Egypt, Rome, and Greece. Ancient Egyptians believed it symbolized life and wore it for protection. It was also thought to instill courage and creativity. The name 'carnelian' is derived from the Latin word 'caro' or 'carnis', meaning flesh, referring to its reddish color.

In the field, carnelian can be identified by its distinct translucent orange-red to reddish-brown color, waxy to vitreous luster, and conchoidal (shell-like) fracture. It is often found as tumbled pebbles in riverbeds or as nodules and fillings in geodes within volcanic or sedimentary rocks. It can be found globally, with significant deposits in India, Brazil, Uruguay, Madagascar, and the United States (e.g., Oregon). When identifying, look for its characteristic warmth in color and lack of visible crystal grains.