Blue Goldstone

Hardness: 6.5 (Mohs scale, but it's glass), Color: Deep blue with glittery specks (due to copper inclusions), Luster: Vitreous to metallic, Crystal Structure: Amorphous (being glass), Cleavage: None, Specific Gravity: Approx. 2.5-2.8

Goldstone was first invented by the Miotti family in Venice, Italy, in the 17th century. It is created by melting silica glass with copper or other metal oxides (like cobalt or manganese for blue), and then controlling the cooling process to allow tiny metallic crystals to precipitate and grow within the glass, creating the characteristic sparkle (aventurescence). It does not have a geological age in the traditional sense, as it is manufactured.

Blue goldstone is almost exclusively used in jewelry, such as beads, cabochons, and carvings, due to its attractive sparkling appearance. It is also sometimes used in ornamental carvings and decorative items.

Goldstone is not a natural mineral or rock. It is a type of glittering glass made in a low-oxygen reducing atmosphere. The most common color is reddish-brown, containing microscopic crystals of copper, which gives it a metallic, sparkling appearance. Blue goldstone, as seen in the image, is made with cobalt or manganese to produce the blue color and often contains copper or other metallic inclusions for the sparkle. Although it is man-made, it is often sold and used in jewelry like natural gemstones.

Blue Goldstone is readily identified by its characteristic deep blue color and evenly distributed, highly reflective, glittery inclusions that resemble stars. It is often faceting to enhance its sparkle, as seen in the bracelet. It is always man-made, so it is not 'found' in nature but rather purchased from manufacturers or gem dealers. To identify it in the field (or store), look for the uniformity of the glitter and the absence of natural imperfections typical of genuine minerals. Its sparkle is usually more intense and even than many natural aventurescent minerals.