Goldstone / Bluestone

Goldstone is a type of glittering glass made in a low-oxygen reducing atmosphere. The finished product can take a smooth polish and be carved into beads,figurines, or other artifacts suitable for semi-precious stone, and in fact goldstone is often mistaken for or misrepresented as a natural material. Another common name for the material is aventurine glass.It is also sometimes called "stellaria," "sang-e sitara" or "sun sitara" for its starry internal reflections, or "monk's gold" or "monkstone" from folkloric associations with an unnamed monastic order. The most common form of goldstone is reddish-brown, containing tiny crystals of metallic copper that require special conditions to form properly. The initial batch is melted together from silica, copper oxide, and other metal oxides to chemically reduce the copper ions to elemental copper. The vat is then sealed off from the air and maintained within a narrow temperature range, keeping the glass hot enough to remain liquid while allowing metallic crystals to precipitate from solution without melting or oxidizing. Goldstone also exists in other color variants based on other elements. Cobalt or manganesecan be substituted for copper; the resulting crystals have a more silvery appearance and are suspended in a strongly colored matrix of the corresponding ionic color, resulting in blue goldstone or purple goldstone respectively.