This specimen features four very rare minerals: chlorophoenicite, hetaerolite, hodkinsonite and zincite. The Sterling Mine is the co-type locality for zincite. While there are now many “localities” for zincite, the majority of them are slag occurrences and the Sterling and Franklin mines (along with some other named openings into the same ore bodies) remain the only two with notable specimens of “natural” zincite. Zincite is a very common mineral here, but crystals of any size are very rare. The zincite on this specimen is mostly in the form of balls of very tiny, tightly packed hemimorphic pyramids, but there is at least one radiating aggregate of distinct, steeply pyramidal, crystals.
Chlorophoenicite and hodkinsonite are also essentially unique to the Franklin and Sterling mines. The TLs are, respectively, the Buckwheat and Hamburg mines, which are just different parts of the “Franklin Mine” in the broader sense. The TL for hetaerolite is the Passaic Mine (Pit), which is just another opening in the same ore body as the Sterling Mine.
The first three pairs of photos have essentially the same scale – the FOV is ca 2.4 x 3.5 mm.
The first pair of photos (FOV 2.4 x 3.6 mm) shows some of the chlorophoenicite aggregates, alogn with some of the yellow zincite “balls”, both sitting on deep flesh colored hodkinsonite. Chlorophoenicite is easily stained. In this case, it looks distinctly tan.
The second pair of photos (FOV 2.4 x 3.55 mm) shows more of the flesh colored hodkinsonite, along with the radiating, steeply pyramidal zincite crystals. The black crystals at upper left are hetaerolite – not franklinite. These are all small crystals. The largest zincite is 0.3 mm long. The hodgkinsonite crystals are mostly < 0.2 mm on edge. This sort of hodgkinsonite is typical of the Sterling Mine. Large, deeply colored, crystals such as those from the Franklin Mine were never found here. (The largest reported hodgkinsonite crystals from here are perhaps 3 mm.)
The third pair of photos (FOV 2.35 x 3.45 mm) shows some of the hetaerolite crystals, apparently in parallel growth. In the one case where a similar aggregate was analyzed (via Raman) it was apparently growing on franklinite – presumably epitactically. (Hetaerolite is also known as an exsolution in franklinite.)
The fourth pair of photos (FOV 6.4 x 4.4 mm) is a broader view (at half the magnification) showing a larger aggregate of hetaerolite on hodgkinsonite.
FOV in the next-to-last photo is ca 1.7 cm.
All of these mineral grow in a seam in ordinary “red ore” – i.e. franklinite/willemite with almost no calcite. This is the next-to-last specimen of this material that I have.
Single item shipping weight (no case) is 4.1 oz (116 g). For shipments outside the USA, up to a total weight < 8 oz (225g), this can be combined with items from this or other auctions for the same postage.
Within the USA, postage for total weights up to 13 oz ranges from $4.50 to $6.50 (including packing etc) regardless of destination. Above 13 oz, I will use “own box” Priority Mail. The rate, including packing, varies by destination from $7.25 to $9.50.
See my updated “Shipping Policy” for details.
