that is the african opal, not the australian opal. african opal did not had really good quality and easy to break if that is not put in the water for the long time. However if you put the african opal in the water, the opal chatoyance would disappear.
well in the western country people did not focus on the grammar, the only measurement is they understand it or not. but thanks anyway to point out the mistake due to sometimes the spoken english did not follow the grammar.