Month: November 2019

Opals

Australian Boulder Opal Opal is a hydrated amorphous form of silica with a water content ranging from 3 to 21% by weight but usually between 6 and 10%. Opal is deposited at low temperature and may be found in fissures of any kind of host rock including sandstone, ironstone, basalt, marl and limonite. Opal is …

Opals Read More »