It has been a little while, but I have my next Drunk on Geology entry - Black Opal. Black Opal is a wine from Australia made by Mildara Blass.
In relation to geology, the back of the bottle reads:
"Black Opal is a collection of contemporary wines names after the alluring black opal gem found only in Australia."
So what is a Black Opal? Apparently it is "the rarest and most valuable type of opal." Is it a darker greenish opal variety with black and golds flecks, where opal is a hydrated form of silica (or quartz). The black opal often contains a rainbow type iridescence to it, making it a very pretty gemstone.
A Black Opal
As I have mentioned before I am not a wine specialist but in general the wine is dry, but smooth. Not as harsh as other dry wines.