K-Feldspar var: Adularia (twins)

Item Description

This is a fine quality and eye-catching Adularia specimen from the Alps of Switzerland. Adularia is a variety of Feldspar, and is defined on mindat.org as a, "more ordered low-temperature variety of Orthoclase or partially disordered Microcline". The crystals are almost always more angular and compressed than higher temperature Feldspar (specifically K-Feldspar in this case). This piece features several sharp, well-formed, colorless, very lustrous, tapered twinned crystals, aesthetically sitting on matrix. The entire group measures 3.2 cm at its longest dimension. No major damage that I can see. The crystals have very good luster for the material, they can often be dull, but these have a distinct vitreous quality on the surface. If you're a fan of Feldspars, Alpine minerals, or just interesting crystal morphology, do not miss out on this attractive specimen from this Swiss Alpine locale.
This piece comes from the collection of John Dagenais (#JD-412), a collector from the Pacific Northwest. John started collecting in 1969 and progressed to micromounting, and later built suites of specimens from the Chuquicamata Mine in Chile, the Tsumeb Mine in Namibia, the Majuba Hill Mine in Nevada, the Black Pine Mine in Montana and the Tintic District in Utah, among other places. You can visit John's mindat profile at https://www.mindat.org/user-647.html.