Perhamite, Page 1

Perhamite is a calcium aluminum silico-phosphate and one of the few phosphate minerals to contain silica (which will be important later on). It was originally discovered at the co-type pegmatite localities of Bell Pit (1975) and Dunton Gem Mine (1976), Newry, Oxford County, Maine. The research, testing and naming of this mineral was published in the December, 1977 issue of Mineralogical Magazine, P. Dunn, D. Appleman, et.al.

A Member of our Faculty -

The mineral was named in honor of Frank C. Perham of West Paris, Maine. Frank is a Faculty member of the Maine Pegmatite Workshop and we are honored to have him with us. You can read a little more about Frank on the Faculty page, or see some images of Frank on a separate page.
NEW Information : Frank Perham had a chance to mine his own specimens of Perhamite in 2006-2007, and recovered what is now a new World Record of a single sphere. It measured 14mm, surpassing the old record of 11 mm. He also recover 3-4 specimens that were in the 11-13 mm size. All specimens are now in the private collections of the miners.

Mineral Data

Perhamite has a Hardness of 5.0 to 5.5, SP @2.65 and is hexagonal and brittle. The Color ranges from creamy light yellow, light brown/tan, white to colorless, opaque to transparent. Pink specimens were found on a matrix of montebrasite, but faded upon light exposure or the loss of free water when dried. The specimens resulted as white crystals. Specimens most commonly present themselves as spherical, but rosettes have been found, although very rare. Individual spheres are normally in the 2-4 mm size range, but record sizes have reach 11 mm.

The matrix for Perhamite is quite similar at the four localities in Maine we have found it at. Albite and cleavelandite feldspar are the most common matrix, with quartz a close third. Additionally in Maine we have found Perhamite on matrix of microcline feldspar, montebrasite, pollucite, montmorillonite, green and pink tourmaline crystals, muscovite mica, quartz, cassiterite and columbite crystals. Perhamite is closely associated with fluor-apatite. The apatite is either in crystalline forms or as a encrusting botryoidal-like coating around or upon the Perhamite itself (actually coats the surfaceof the perhamite). Deposition of perhamite always seem to be late in the paragenesis of the pegmatite, during a late silica phase, which includes small colorless and clear quartz crystals. The perhamite and its associated fluorapatite always seem to be the very last thing to develop, usually in any type of pocket, seam or void of any kind.

See Slides

A true, hypothetical single crystal of Perhamite is a thin hexagonal plate. To date, such a crystal does not exist naturally in nature. In all the specimens found, we have never found an individual crystal of Perhamite, only the compound forms of spheres, rosettes and encrustations.

At the center of a hypothetical crystal plate is a "central growth point" or point of origin, where all crystalline growth developes from. The image below left is of a sphere broken open, and you can see the central point of growth (arrow). This feature is an aide for diagnosing perhamite in the field, easily seen with the naked eye.

Generally these plates grow in parallel with each other at all times, at least they try too, all from the same central point of growth. As the crystal plates grow, the compound accumulation ends up forming certain shapes. The most common shape found is spherical, while rosette shapes and tight, compound clusters are found also.

Diagram above: Illustrates details discussed above.
Photo left: central growth point; note hexagonal outline.

See Slides

Localities in Maine

The original Type Locality specimens tested were 1mm or less (see item A. below). Massive, solid perhamite was found in Australia afterwards, but it is my understanding that none of it was crystalline. Since then we have located crystalline specimens, usually much larger then the original finds, at four additional pegmatites in Maine (see B. & C. below):

	A. In Newry, Oxford County, Maine: Type Locality
		1. Bell Pit, Plumbago Mountain, Hall's Ridge - Type Locality, Testing Specimens 1 mm spheres 2. Dunton Gem Mine, Plumbago Mountain, Hall's Ridge - Type Locality white botryoidal clusters 3. Whitehall Quarry, Plumbago Mountain - confirmed visually by author.
	B. In Greenwood, Oxford County, Maine:
		1. Harvard Quarry, Noyes Mountain : 1 specimen, compound crystals, 1.5 mm or less, associated with fluorapatite on matrix of albite and cleavelandite. See our slide show.
		2. Tamminen Quarry : 1mm spheres, in cleavelandite void - 1 specimen, no photograph.
		3. Emmons Quarry, Uncle Tom Mountain - Actively mining: specimens from <1 mm to 9.5 mm. Associated with fluorapatite. Matrix of albite, cleavelandite, elbaite tourmaline, microcline, montebrasite, montmorillonite, muscovite, pollucite, quartz, cassiterite and columbite. See photographs.
	C. In West Paris, Oxford County, Maine:
		4. Ski Pike Quarry (or Cobble Hill Quarry - old name): Individual spherical compound crystals, to 14 mm (World Record - Frank Perham miner). Also, tight, compound clusters common. Associated with fluorapatite. Matrix albite, cleavelandite, quartz, elbaite.

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.

Page 1

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Slide Show of Perhamite

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