Dims: 2.6 x 2.0 x 0.7" (6.6 x 5.1 x 1.8 cm)
Wt: 1.3 oz. (36.2 g)
Springfield Butte, Springfield, Lane County, Oregon, U.S.A.
Another large thumbnail specimen, this piece consists of a layer of fibrous, radiating Natrolite that covers one side of a thin, quartz-coated basalt slab. The Natrolite crystals are in excellent condition and reach lengths of 0.3" (8 mm) on average. They are far too thin for one to effectively study without high magnification, but their form is likely very good. All have a milky-white coloration and a pearly luster, and though individual crystals would likely be noticeably transparent, they are essentially only dimly translucent at best when clustered. Resting among the needles are many small calcite crystals whose dimensions range from less than 1 mm square to 0.2 x 0.1 x 0.1" (5 x 3 x 3 mm). The larger crystals have a double-terminated scalenohedaral form, whereas the smaller crystals form is rhombohedral (see the close-up image). All have a milky-white coloration and a dull waxy luster, and are translucent.