The Sterling Mine is the type and only know locality for lawsonbauerite. It is a very rare mineral here.
This specimen features two small cavities with lath-like crystals similar to those shown on p. 636 of Pete Dunn’s “Franklin and Sterling Hill, New Jersey: the world’s most magnificent mineral deposits”. This habit is distinctly different from that of mooreite (a related mineral) – see minID VEN-LUD or Dunn p. 638.
A sample from this find was also analyzed via qualitative EDS. (See the “Analysis” tab.)
Uncalibrated EDS is not, by itself, sufficient to prove that this is lawsonbauerite. However I have also provided a scan for a known mooreite sample (made with the same equipment at the same time). While peak heights in such scans can not be compared simplistically, it is clear that the lawsonbauerite is Mn dominant – as it should be. Together with the habit, this indicates lawsonbauerite rather than mooreite. (While torreyite, the Mg analogue of lawsonbauerite, can have a habit very similar to lawsonbauerite, one would expect a scan more like that of mooreite.)
The lawsonbauerite cavities occur in a matrix of layered sussexite, pyrochroite, and rhodocrosite. The layers are thin, and only a few have narrow cavities with freely growing crystals.Most of the pyrochroite consists of inter-grown crystals, but there is one fairly good isolated crystal.
The first pair of photos (FOV 3.6 x 2.3 mm) show the best and most characteristic lawsonbauerite crystals.The crystals in the center are about 1.2 mm long. The black stuff is pyrochroite. These photos can be seen in stereo on Mindat under minID 532-JNJ.
The second pair of photos (FOV 2.3 x 3.4 mm) show the other lawsonbauerite cavity. The main group of crystals is about 1.4 mm tall, but it is not well exposed and the characteristic “finger like” habit is not so evident.
The next three photos (FOV 2.9 x 2.0 mm) show the best pyrochroite crystal (1.4 mm) on the specimen. One side of the crystal exhibits complex growth figures. Isolated pyrochroite crystals are not common.
In the full-view photos, the white stuff is sussexite (sometimes intergrown with rhodochrosite). The black stuff is all pyrochroite. There is no franklinite or hetaerolite here.
Single item (small box) shipping weight 2.3 oz. For shipments outside the USA, up to a total weight of 8 oz (225 g), this could be combined with other items from this or future auctions for the same postage. If you wish to keep an “open box”, let me know.
For shipments within the USA, there is a nominal increase of about $0.20 for each additional ounce. Above 13 oz I will use “own box” Priority Mail ($8.75).
