An albite crystal collected from a pegmatite near Bethel, Maine shows long narrow deformation bands oriented approximately normal to (010). In thin section, between crossed nicols, these bands become readily visible due to the difference in extinction position and the bending of intersecting twin lamellae and are associated with small boundary fractures and irregular, but progressive, extinction changes from band to undeformed host (Fig. 1). The only twinning present is abundant fine regular albite lamellae regarded as secondary in origin (Vance, 1961; Seifert, 1964). Both optics, by the 5-axis feldspar method with 2VZ=79°, and x-rays, average (131) —2θ (131) = 1.20, indicate the albite crystal is in the low temperature ordered structural state and roughly agree with a chemical analysis indicating the crystal has a composition of An7.

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