Lower Silesia? I already read that opal is mined in a place called Szklary.
Yes, exactly! Opals in Poland are mainly found in Lower Silesia and this one was found in Szklary-Huta :)
Opal used to be very valued in antiquity, because it was rare. The only place where it was known to be found in Europe was apparently today's Slovakia. In the 19th century vast deposits were discovered in Australia and opal has become the national gemstone of that country :)
I love the colour :)
Me too :)
They're prone to cracking unfortunately.
Yes, apparently they can break like glass.
Other pieces found at that location during a half an hour walk:

Szklaryopals.jpg