The SEM micrographs of the fracture of CEPBS foam showed that after the incorporation of CE, the cell size distribution became uniform, cellular wall became thin, and the cell structure turned oval to pyritohedron
. The highest expansion volume ratio of CEPBS sample was more than 14 times.
The best crystals are pyritohedrons
measuring 7 or 8 mm, found as floaters in a pale brown vein of carbonates.
Some of the pyrite crystals are simple, lightly striated pyritohedrons
, while others are distorted and show complex morphology, but all are brilliantly lustrous: these little specimens would grace anyone's suite of worldwide pyrites.
Spruce Ridge pyrite crystallizes in cubes, pyritohedrons
, and combinations thereof.
Pyrite is very common as beautiful, sharp, octahedral, cubic or cuboctahedral crystals (but never as pyritohedrons
Troy Consolidated Mines, Ltd.; golds from the Smithsonian, including the great, famous, foot-high "Seaweed"; The Literature of Crystallized Gold (with fine old crystal models and drawings)--Geo-Literary Society and the Gemological Institute of America; Gold Mining Memorabilia--Herb and Monika Obodda; Gold From Unusual Places, and Gold Fakes (including a really quite handsome specimen of gold-plated pyrite, with perfect 2-cm pyritohedrons
)--Society of Mineral Museum Professionals; the Fricot nugget (really a brilliant crystal specimen about 45 cm wide, found in California in 1865--it is shown on the front and back cover of the second Gold Issue, vol.
The hubnerite, in turn, forms thick growths, like a prickly underbrush, on slightly rough-faced pyrite pyritohedrons
to 5 cm on edge, and groups of same to 15 cm across.
Good specimens of barite, enargite, octahedral pyrite, pyrite pyritohedrons
, and good iridescent pyrite along with quartz crystals were collected.
In addit ion there were Scandinavian classics like loose, sharp 2-cm pyritohedrons
of cobaltite and sharp, lustrous pseudo-octahedrons of glaucodot from Sweden; well crystallized leucophanite, columbite and thortveitite from Norway; and richly brownish red, euhedral crystals of eudialyte to 2 cm in complex ultra-alkaline matrix, not from the Kola Peninsula, Russia, but from 19th-century localities in Greenland.