Smarite

Smarite is a mineraloid, a naturally occurring substance that has mineral-like properties but is not considered a true mineral. It is a type of opal, specifically a variety of chalcedony that exhibits play-of-color. The term "smarite" is less commonly used than "opal" and often refers to opal found in specific geological contexts.

The composition of smarite is hydrated amorphous silica, essentially silicon dioxide with water molecules incorporated into its structure. Its physical properties include a vitreous luster and a hardness of about 5.5 to 6.5 on the Mohs scale, similar to other opals. The characteristic play-of-color is due to the diffraction of light by microscopic silica spheres within the material. The size and arrangement of these spheres determine the colors displayed and their intensity.

Smarite, like other opals, is formed through geological processes involving silica-rich solutions, often in sedimentary or volcanic rocks. It can be found in various locations worldwide. Its value and appeal are primarily based on its color, clarity, and the intensity of its play-of-color, making it suitable for use in jewelry and ornamental objects. However, due to its amorphous nature and water content, smarite can be susceptible to dehydration and cracking if not handled and stored properly.