kyanite crystals in quartz - São José de Safira, Minas Gerais, Brazil - hand/display specimen Tuffs are light colored

Tuffs are light colored

Radiocarbon dating of broken and undisturbed layers would bracket the age of the fault rupture

with crystal faces as they came from the mine and perfect terminations

It would be instructive for students to compare these two dune sands - both fine-grained but very different in color

kyanite crystals in quartz - São José de Safira, Minas Gerais, Brazil - hand/display specimen Tuffs are light coloredkyanite Al2SiO5 Kyanite forms when aluminum rich rocks are metamorphosed, and is frequently found in schists that formed at medium to high pressures and lower temperatures in areas of regional metamorphism. At higher temperatures, kyanite converts to sillimanite. Occasionally the metamorphism produces a pegmatite with large crystals that form when a fluid rich magma allows rapid movement of atoms. These large crystals of kyanite and the surrounding