Modern Geology, v. 1, p. 283-300.
Sharp peaks suggest high degree of crystallinity and compositional heterogeneity.
HS190.3B shows reflections that are present in the pattern of the Alpine reference material but do not appear in the list of peaks calculated by Borg and Smith. Intergrowths prevent giving grain sizes for individual minerals. Fine-scale intergrowth of quartz and dumortierite make positive identification of quartz or feldspar very difficult.