Conway granite near where it is mined. The Old Man of the Mountain, a famous geologic feature in New Hampshire (which collapsed in 2003) was made of Conway granite. The formation is found throughout the lower areas of the central White Mountains, such as Franconia Notch, Crawford Notch, the center of the Pemigewasset Wilderness, and the Saco River valley. Other exposures of the formation include the Belknap Mountains south of Lake Winnipesaukee. Conway granite Conway granite is a typically pink mineral-rich igneous (or mesoperthitic) biotite granite. It is amphibole-free and of coarse particle size (with portions of the rock fine-grained or porphyritic).
Harz granite crystals can be up to 18 mm across. Birkenkopf granite was quarried on the Großer Birkenkopf hill south of Hasselfelde. It is a medium-grained granite with blue-grey coloration. In the quarry 30 to 40% blocks of stone could be used for sawing and 50% of exploitable rock debris could be obtained. The quarry closed in 2009. Birkenkopf granite contains 31.3% quartz, 42.6% alkali feldspar, 20.4% plagioclase feldspar, 5.4% biotite and chlorite as well as 0.3% ore minerals like magnetite, pyrite and hematite. The quarry for Wurmberg granite was situated about 2.5 kilometres north of Braunlage and 250 metres high on