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Volume 3, page 192, 1918 Some months ago there was received at the National Museum for identification a peculiar rock, evidently a somewhat
altered volcanic breccia, so injected with a blue coloring matter as to suggest lapis-lazuli. The manner in which the
coloring matter was distributed, a portion of it in the cementing material and a portion actually replacing the original
rock fragments, suggested its secondary origin and invited careful tests to ascertain its true nature. Thin sections
under the microscope showed the coloring matter to occur as minute scales without crystal form and very irregularly
distributed. These had the refractive indices and gave the chemical reactions of lazulite, which is a hydrous phosphate
of aluminum, iron and magnesium. It is an interesting occurrence since it closely simulates, as above noted, lapis
lazuli (lazurite), which has, however, a quite different composition.
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