Crystal opals are found in almost every area where gem colored opal is formed. Lightning Ridge has produced some of the best crystal opals I have ever seen, with Coober Pedy a close second.
Australian opal mining fields are one of the most prevalent in gem Crystal opal. Top-quality crystal opal from Lightning Ridge comes in the form of nobby opal, while the gem quality that comes from Coober Pedy is formed in Seam opal. It is unexplained why only Lighting Ridge is the only place that nobby opal occurs.
Brazilian Opal is now becoming more popular with some very lovely gem opal popping up in markets all around the world. Brazilian opal mostly produces crystal opal and has had some stones that match the gem quality of Australian crystal opal.
Some crystal opals from Lightning Ridge have reached prices of over $2000 per carat, on the opal mining fields, making crystal opals quite sort after gems.
Crystal opal is one of the easiest opal to cut and polish by an opal cutter because you can see straight through the opal by holding it up to the light. You can see impurities very quickly and estimating weights and sizes are simple.
The most valuable Crystal opals have a high cabochon or dome to give the opal depth that most other types of opal usually can’t produce. Crystal opals also are common to polish both sides of the opal, making the setting and design of jewelry very exciting and sometimes challenging.
Black opal is the most expensive opal in the world, but crystal opal is second in the running for most valuable opal.
Crystal opals can have many different patterns from Harlequin pattern to a flat sheen pattern.
I have some crystal opals in my collection that I have had for 20 years and will not sell them because I may never see this quality again ever!