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Field Observations
 Perhamite can be difficult to notice in the field because of its average size, 1-3 mm, but not impossible. A unique clue to watch for is a black, water-soluble mud which often conceals the specimens. This mud rinses away easily. Also Perhamite can mimic the appearance of cookeite, but a simple hardness test can make the determination. Cookeite will bend, crush or bruise under fingernail or needle pressure, while Perhamite will break. Also by visually inspecting broken specimens, Perhamite will always have that "central growth point", visualized as a darker spot dead center of the sphere (photo above). Cookeite will not. |
Cleaning
A good unltrasonic cleaning will usually clean most specimens and a lite scrubbing with a soft toothbrush and soap works well also. But as noted above, this phosphate contains silica. Because of this, Perhamite is not affected by cleaning acids like oxalic or dilute HCl. Pre-soak the specimens in water, then place in acid to loosen stains, dirt or clays. Keep the time needed to a minimum (we use an ultrasonic cleaner at this point), neutralize acids with an ammonia soak, then into a repeated final rinse of water. Do not use acids if other phosphate minerals are present. If needed, I generally use the Waller Method now to clean perhamite, no matter what. | | You will also see and read about the association of perhamite with fluor-apatite. In some cases, the fluor-apatite will encrust the mineral perhamite, either with an opaque crust or a thin colorless coating. I have found that I can remove this crust or coating of fluor-apatite with Muriatic Acid (20% hydrochloric acid) and not harm the perhamite underneath. Specimens immersed for 3-10 minutes reveal that the fluor-apatite is completely removed. Be careful to rinse once, then neutralize the specimen with ammonia, then rinse very well. Specimen I would not normally keep have been so treated, revealing a superb perhamite specimen. |
My Observations
Perhamite was first discovered at the Emmons Quarry in the 1980's by Gene Bearss of Sanford, Maine, shortly after the publication of the mineral. Except for two episodes of Perhamite my partner and I recovered at the Ski Pike Quarry, Cobble Hill, West Paris, Maine, the Emmons Quarry has produced the best specimens recovered to date in my experience. Although not abundant, we have found many exceptional specimens in the 14 years of work at the Emmons. The largest single sphere(s) from the Emmons Quarry (9.5 mm) has a matrix of quartz/cleavelandite and is on display at Perham's of West Paris Store Museum, West Paris, Maine. An image of this specimen is in the slide show. | | The better specimens are always found within the Core Zone of a pegmatite, always in pockets and voids. Matrix is usually quartz, microcline, albite or cleavelandite and sometimes other mineral crystals from the pockets. The Core Zone pocket specimens can be quite impressive. Individual spheres can reach an average of 5-6 mm in diameter and clusters can coat any surface, especially quartz and the feldspars. The record in my experience is a 14 mm diameter, individual sphere. We have also found Perhamite in the Intermediate Zones above and below the Core Zone. In these Zones, Perhamite is always in vugs and voids of albite or cleavelandite and always of smaller sizes (<1 mm to 2 mm). | | As mentioned under cleaning, some perhamite specimens are coated by a fluor-apatite, botryoidal or crystalline, and sometimes a carbonation apatite. Any of these can be removed by acids, leaving the perhamite pristine. The incrustation was very late and does not seem to have effected the perhamite surfaces. | The absolute best specimens are found in elbaite tourmaline pockets. We have found so at two localities. The specimens are colorless, transparent on edge, extremely well crystallized and show no signs of any oxidation or impurities. Although clusters generally look white, the crystal plates on edge are transparent and colorless. We have found perhamite attached to green elbaite tourmaline crystals, on the terminations and side prisms, but this hosting is extremely rare (rarer then the tourmaline).
Follow the Slide Show link below to see some examples of the perhamite we have recovered. |
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