Diabase + pegmatite
I just recently came back from a week long trip to the province of Blekinge here in Sweden. Its an awsome province with beautiful deep forests and I can recommend a trip to it to anyone who loves nature. But be sure to bring something against mosquitos and ticks. The humid climate near the Baltic sea makes it a paradise for ticks.
It was a course in making maps of the bedrock, the petrology and structures. Mostly we found intrusive granites and more or less gneiss and granite-gneiss with pegmatite intrusions – the most common types of bedrock in here south east of Sweden. But one unusual loose rock caught our attention.
The theory my professor gave us was that it probably was a piece of diabas with (from the intrusion loosened) megacrysts of pegmatites in it (microcline and red quartz). The area is rich in pegmatites and diabase intrusions so the theory of origin made sence, however he had never seen anything like it before and had to base this on a qualified assumption. I presume its an unusal find or has someone found anything similar? No, its not my finger…
