Quartz from selected localities.
Brazil | |
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Vlach, S. R. F., Ulbrich, H. H. G. J., Ulbrich, M. N. C., & Vasconcelos, P. M. (2018). Melanite-bearing nepheline syenite fragments and 40 Ar/39 Ar age of phlogopite megacrysts in conduit breccia from the Poços de Caldas Alkaline Massif (MG/SP), and implications. Brazilian Journal of Geology, 48, 391-402. | |
Horváth, Menezes, Toft ollections - confirmed by XRD & microprobe |