What does crazing in opal refer to?

Crazing in opal refers specifically to a network of tiny fractures that develop within the stone, primarily as a result of moisture loss. Opals are hydrous minerals, meaning they contain water in their structure, and if they become too dry or experience rapid temperature fluctuations, it can lead to these minute cracks forming. This phenomenon can significantly affect the stone's appearance and value; the presence of crazing can detract from the opal's overall beauty and brilliance, as it disrupts the smooth play of color that is characteristic of high-quality opals. Understanding this process is crucial for anyone involved in evaluating or selling opal, as it highlights the importance of proper care and the environmental conditions to which opals are exposed.