Chalcedony

Mohs hardness of 6.5 to 7, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture, specific gravity of 2.58 to 2.62.

Formed at low temperatures from aqueous solutions rich in silica, commonly depositing in cavities of volcanic and sedimentary rocks.

Widely used in lapidary arts, ornamental carvings, jewelry, and collector specimens.

Chalcedony serves as the parent mineral for many well-known varieties such as agate, jasper, and onyx. Ancient civilizations used it extensively for carved seals and talismans.

Identified by its waxy luster, conchoidal fracture, and microfibrous structure under magnification. Found globally, especially in Brazil, India, and the western United States.