Are there precious stones in Edinburgh?
Edinburgh is built on a huge block of granite and you said that gems can often be found in granite. Why aren’t we looking to Edinburgh as the gem-Mecca of the north?
We put this question to Ian Mercer:
Edinburgh actually is partly built on, or the castle is certainly built on, the remains of a volcano. Actually it's a basalt volcano. Yes, you can get gems in basalt but if you search all the basalt around the world looking for gems you'll only find gems in relatively few, relatively speaking. Before you try to seek permission to dig up Edinburgh I'd think about the geology first.
Chris: There's probably better things to find in Edinburgh like whiskey, for example!