The first thing to note about opals is that they are all incredibly unique and individual. Most show flashes of colour called ‘play of colour’. However, if no flash is seen it is called ‘common opal’ and shows ‘opalescence’.
There are so many varieties in opals depending on…
Body colour i.e. black/white
Flash colour and pattern i.e. pinfire, harlequin
Locality of origin i.e. Ethiopian/Mexican
What the opal has formed in i.e. boulder/wood
With all these combinations it makes Opals truly distinctly unique.