St. Kilda Oddity

 Granite/Dolerite Breccia, St. Kilda, Scotland

I collected this rock two years ago on the remote island of St. Kilda, off Western Scotland. It is about 9 inches long, about the size of an enormous russet potato.  I was stunned by the structure of the rock, composed of angular blocks of dolerite (Basalt) "floating" in a granite matrix. This was the largest one I could carry - but much of the island ( a World Heritage historical site) is made up of this stuff. No gem value, obviously, but just a wonderful piece of geology.