We’ve visited the Half Dome Granodiorite before, both as a crushed “sand” and as a deskcrop. Well, it’s time to visit this beautiful rock once again, this time in the form of a glacial erratic, in its natural habitat.
This particular erratic is located on the shores of Tenaya Lake in Yosemite National Park. It’s an example of the equigranular phase of the Half Dome Granodiorite (there’s also a porphyritic phase). If we take a closer look you can see some of the minerals that make up this rock: plagioclase feldspar is most abundant, followed by quartz, K-feldspar, hornblende and biotite. There’s also accessory sphene (titanite) but I doubt you’ll spot it at this resolution.
And I’d be remiss if I didn’t let you in on the even more spectacular view from this vantage point.
Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!