opal

ID: skos/Commodity/MIN4EU/opal

Item class: Concept

Label (en): opal

Label (hu):

Definition (en): Opal is a hydrated amorphous form of silica; its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid - http://en.wikipedia.org/wiki/Opal

Definition (hu):

Concept scheme: Commodity

Broader concept: MIN4EU list of commodities