Fig. 4. This photomicrograph is from a granite in the Cargo Muchacho Mountains in southeastern California (USA). The plagioclase in the wall rock diorite has an average composition of about An₄₅. The maximum thickness of the quartz vermicules is now much larger than in the granite at Temecula (Fig. 3). Sphene (brown) and epidote (reddish) are colored grains in photo. Quartz occurs in clear grains (white, cream).