Opal is a hydrated amorphous form of silica with a 3 to 21% water content. Because of its amorphous character (meaning it has no crystalline structure), it is classed as a mineraloid rather than a mineral. It is deposited at a relatively low temperature in the fissures of almost any kind of rock. Its internal structure makes it diffract light. (more…)
Read More
Dendritic Opal
The dendritic opal is a whitish-grey or colorless chalcedony. Though it is called to be a type of opal, (more…)
Read More