me and my friend were digging one day because we were bored we had discovered large rock about 6” by 4” when we cracked it open it had shiny white and black crystals, We have discovered that it is granite and worthless to sell, now we are wondering what to do with it?
It's a really nice example of granodiorite, common to the north central Cascades. The beautiful black tabular crystals are hornblende, the milky minerals are quartz and the clear minerals are a plagioclase (feldspar mineral). The rounded nature of the rock speaks to being shaped by travels in a river and perhaps, rolled around by the continental glaciers.
If you collect rock samples from the North Cascades, this is a good one to keep. Otherwise, granitic rocks make nice landscape rock. Check around your neighborhood to see if someone is landscaping with granitic rocks that look similar. You can add to their landscaping.
Thank you for asking!