Chalcedony is an unspecific term for amorphous to crypto-crystalline accretions of the mineral silica (SiO2), most often formed by precipitation from aqueous solutions in rocks. The semi translucent, silky to fine-crystalline varieties in soft pinkish to blue hues as here seen are popularly known as a chalcedony roses and much in demand with gemstones collectors and in circles of esoteric healing.