When I came across my first floating opal, I hardly knew what It was. I purchased the item from my then-favorite vendor at McKinney Trade Days last year. The piece must have cost me between 2-5 dollars, and liek all jewelry that I have begun to find, I immediately went home and tried to do some research on the piece.
The pendant is teardrop shaped glass, with a nicely worked silver cap, but not in the traditional tulip shape. I immediately knew the opal chips for what they were because of my longstanding love for the stone. I know now that they are suspended in water... not oil. I found that out when I came across my second floating opal- gold tulip capped and with a round globe. I've included some pictures to show as examples.
Some information about the opal as a stone:
http://www.gemstone.org/gem-by-gem/english/opal.html ( the most thorough link on opals I've ever seen!)
And informaton about floating opals: