Graphite with growth spirals from marbles from
Namib Grube, Wlotzkas Baken, western Namibia


For more information, see Rakovan & Jaszczak (2002) American Mineralogist 87, 17-24.

Remarkable spiral showing a transition from rounded steps
near the center, to polygonalized nearer the crystal's edges.
John A. Jaszczak collection and photo.

Interesting spiral with wide, rough terraces that seem to be
grouped in step pairs. (bottom right:) Image taken with polarized light using
Differential Interference Contrast (DIC).
John A. Jaszczak collection and photo.

Sub-millimeter hexagonal hillock and
growth steps on the surface of
a graphite crystal (exposed from calcite).
John A. Jaszczak collection; John Rakovan DIC photo.

1.5mm graphite crystal showing a
12-sided growth spiral with two kinds
of steps: one set parallel to <11.0>
and another set parallel to <10.0>.
This crystal is from near Usakos.
John A. Jaszczak collection and photo.

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