Individual crystals form subhedral
(predominant) to euhedral cubes and octahedra (which may be tightly intergrown in some areas) that do not exceed 0.
Samples from the host rocks contain 30 to 60 % anhedral quartz and subhedral
and anhedral feldspar phenocrysts ranging from 5 to 12 mm in length (Fig.
Magnetite occurs in the sill rock as small black grains, and very rarely as black, crude subhedral
crystals up to 5 mm in diameter.
The porphyritic monzogranite contains two populations of subhedral
to euhedral feldspar phenocrysts (1-12 mm) with plagioclase generally more abundant than K-feldspar, constituting 30 35% of the rock.
Pyroxene: The pyroxene is mainly represented by both, ortho- and clinohypersthene, occurring as small euhedral to subhedral
prismatic crystals and square or equant basal sections.
Fluorapatite has been found as a single, subhedral
, yellow glassy crystal approaching 1 cm in a talcose matrix by Jon Ertmann in June 2002; identification was made by Bart Cannon using EDS.
Most of the plagioclase grains are large, subhedral
to euhedral and cloudy.
No euhedral or subhedral
rose quartz crystals have been described.
Instead, the subhedral
shape of the calcite crystals suggests that they are pseudomorphs after gypsum and that the crystal-laminated interval exhibits a primary fabric that records little post-depositional deformation other than compaction.
The freshly exposed surfaces often contain as many as six different mercury minerals, ranging in habit from individual crystals to subhedral
and anhedral masses, and also intimate mixtures displaying various colors.
Zircon grains recovered from the sample were mostly colourless to very pale brown and subhedral
to anhedral in shape, the latter suggesting relatively late magmatic growth.
8 cm rises from a matrix of white subhedral
microline crystals, sharp muscovite books and very dark smoky quartz crystals, the latter to 8 cm.