The article provides information on dumortierite and sapphirine, the two transparent minerals discovered in gravels from Tunduru, Tanzania. The color of the dumortierite was violetish gray and brownish pink while the other mineral consisted of four transparent waterworn pebbles colored gray to violet and red. Aluminum (Al) and silicon (Si) were present in the dumortierite. The author attributes the color range of sapphirine to variable amounts of iron (Fe) and chromium (Cr).