Amphibole, variety Hornblende. This sample is exceptionally pure hornblende. Modern Geology, v. 1, p. 283-300. The clinoamphibole pattern is consistent with hornblende.
All reflections are sharp, suggesting good crystallinity and compositional heterogeneity.
Average of 10 grains. All these properties are consistent with hornblende. Although this sample is contaminated, a combination of Franz Seperator and heavy liquids will probably separate out the hornblende.