传一个和你类似的欧泊，澳洲这边买家的英文描述如下
This solid black matrix boulder opal has been mined from the Queensland boulder opal fields. The ironstone of the opal is brown, similar to our natural matrix opals. These opals have been treated to darken the ironstone and then stabilized to fill any small rough edges at the rear of the opal.
也就是买这类欧泊，体色如此黑的，一般都是碳化后的，使得变彩更明显。不过这是澳洲这边公认允许采用的，但是卖家应该说清楚处理方法，这是基本诚信~
