Just a very unusual specimen, with muscovite seeming to have replaced 3-dimensional lepidolite crystals. From Chuck Houser: "The core zone of the Elizabeth R Mine at the north end of the upper workings was very rich in green muscovite. Pockets would typically contain muscovite, albite, quartz, and minor orthoclase. The muscovite crystals, like the specimen on Rob's website, were somewhat unusual in that they had an elongated 'prismatic' habit, rather than the usual tabular books. Some of these specimens, like the one on the website, were really very good specimens for a species usually overlooked as a secondary 'grunge' mineral."