Tourmaline discovery at the Cryo-Genie mine: San Diego County California
by Anthony R. Kampf,
Ken Gochenour,
Jim Clanin
Allanite-(Ce), (Ce,Ca, Y).sub.2](Al,[Fe.sup.2+],[Fe.sup.3+]).sub.3](Si[O.sub.4]).sub.3](OH), occurs as fan-shaped groups of prismatic crystals in the core zone adjacent to pockets.
Crystals are probably at least partially metamict and can be recognized by their high specific gravity, pitchy luster, and black color. No chemical analysis was conducted on this material; however, because allanite-(Ce) is by far the most common species in the allanite group, we consider it most likely that this is the allanite-group mineral occurring at the Cryo-Genie mine.
Apatite, [Ca.sub.5][(P[O.sub.4]).sub.3](F,OH), has been found in the western portion of the pegmatite as small, gemmy, blue or bright purple crystals on cleavelandite with lepidolite and elbaite, The largest crystal found in this portion of the dike is roughly equant and measures about
13 mm across. On the eastern side of the pegmatite, a single apatite crystal was recovered in the pocket debris after cleaning. It is a slightly etched prism with only partial faces and measures
13 mm across and
6 mm thick. Its color is pale pink beneath an iron-stained surface. Small (<
1 mm) apatite crystals were found on a quartz crystal in the first pink tourmaline pocket (no. 7), and recently a drusy coating of apatite was found in a small vug north of the BAT Pocket. See also under pollucite.
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