Dims: 4.0 x 2.7 x 0.5" (10.2 x 6.9 x 1.3 cm)
Wt: 5.68 oz. (161.0 g)
Esquire #1 Claim, Rush Creek, Fresno County, California, U.S.A.
This specimen consists entirely of crystalline Sanbornite. While the piece shows no definite crystal form, it has the flaky, micaceous crystalline tendencies of the species. Its largest surfaces are freshly-cleaved, whereas its thinner, side surfaces are coated with a thin, white crust or are rust-stained. Actually, it resembles mica in many respects, including its pale, greenish-white color and bright pearly luster. It does not flake as easily, however, and is more brittle than mica. It also lacks the transparence of muscovite and most other mica varieties at thin spots. Other than the aforementioned thin white crust, there is no host rock present.