Schoonmaker Mine (Cramer Mine), Strickland pegmatite (Strickland-Cramer Quarry; Strickland-Cramer Mine; Strickland-Cramer Feldspar-Mica Quarries), Collins Hill, Portland, Middlesex Co., Connecticut, USA

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Located in the Middletown Pegmatite District comprising a swarm of Permian (~260 mya) pegmatite dikes; locally in a north-trending zone, mostly in the Ordovician Collins Hill Formation; but dikes are also present in eastward adjacent Ordovician Glastonbury Gneiss and westward adjacent Ordovician Middletown Formation.

An underground mine in the northern part of the Strickland pegmatite. It was a separate operation and for most of its life was not physically connected to the more famous Strickland quarry and mine to the immediate south and in the same pegmatite. Mostly a mica mine, some feldspar and a little beryl production. The northernmost large dump around the Strickland pegmatite is from this mine. Specimens from that dump should be attributed to this mine and not the Strickland Quarry. The difference is largely academic anyway because they both mined the same pegmatite, the mineralogy, pegmatite zoning, and host rocks of the Strickland Quarry and Schoonmaker Mine are similar. Any specimen can be generically attributed to the Strickland pegmatite. Minerals from host rocks included in list.

The mine was worked from July 1933 to 1945. Charles Cramer leased it to A. O. Schoonmaker Co. of New York City under the name Connecticut Mica & Mining Co. (Willard Northrop operator). Shaft was initially sunk to 120 feet. Mined mostly by stoping updip from the base of the shaft until 1942. Then they sunk winzes to stope lower levels until 1945.

Bartsch (1940) gave this early account:

"The material on the dumps was bright and clean after the previous day's downpour and many fine minerals were plainly visible. The new waste material brought to light many minerals that have been listed as rare. An excellent specimen of amblygonite was found, also some nice crystals of bertrandite in cavities in feldspar, many fine pieces of pink beryl showing the usual zoning, some very fine specimens of deep orange-red lithiophilite in quartz, black sphalerite xls in quartz and an unusually large cavity filled with salmon-red rhodochrosite with masses of micro xls.

"The usual minerals of this locality are now available in excellent material with the exception of lepidolite which seems to be scarce at the present time and this also accounts for the scarcity of colored tourmalines. Spodumene is also uncommon except for its alteration product pinite which is plentiful in various shades of green and brown.

"All of the above mentioned material was found on the Schoonmaker dump as this is the only operation now working."

Little (1942) also gives one of the few written accounts of collecting there:

"One of the finest minerals of especial (sic) interest that was found at the mine last summer was amblygonite, and it was a large size block of white or pinkish color and quite pure. But it looked very much like the albaite (sic) that was so plentiful there, and as amblygonite had never been reported from that mine, doubt was had as to its identity, so only a few pieces were broken off and taken home for further examination. On testing for intumescence, etc., it was found to be amblygonite, and within a few days another trip was made to obtain the rest of the specimen, but on reaching the place it was found to be gone. Probably some other collector had recognized it and taken it away. Subsequently two more fairly good specimens were found these having a small amount of light green tourmaline with amblygonite."

"Soon after this, lithiophilite began to appear on the dump. This was in albaite (sic) with some spodumene and lepidolite, and mostly of a deep reddish brown color, though some was of a lighter brown. It was found sparingly for about a month, and since then none has been seen. Incidentally it might be mentioned that each of the common minerals found at this mine seemed to appear for a short time and then were never seen again, as though they only occurred in small amounts that were soon exhausted, or possibly in veins which were cut across and passed by."

"During September and October much interesting material was thrown out on the dump. Fluorite was found in two forms; as dark purple cleavage pieces, and as nodules that were covered with a grey film, but that fluoresced a beautiful lavender blue. The cleavage pieces were not fluorescent. The fluorite nodules were generally accompanied by bright cubes of pyrite which varied in size up to 1/2 inch on the faces. Some of the specimens had the cubes of pyrite spread thickly over a base of crystallized albaite (sic), the crystals of albaite (sic) being about the same size as those of the pyrite, making very showy specimens. All these latter specimens appeared to have been formed in cavities."

"Late in the fall a considerable amount of gemmy pink and green tourmaline was found. Some of the crystals had a deep pink center and were colorless on the outside, and some were pink at one end and green on the other. These latter were broken across, at least every quarter inch, and the two colors seemed to be end to end instead of grading into each other. Some occurred in an unusual form, as pellets of a quarter inch or more in diameter in a very hard quartz rock, and this required such heavy pounding that the tourmaline was apt to fall out, leaving round or oblong cavities. A few of these pellets were saved and might be cut into gems. Some opaque tourmaline was found in triangular crystals of about 1/2 x 3”, which were a yellowish green on the outside and greyish white inside. As they were in quartz, it was difficult to get them of much length."

"Plenty of the other minerals were found that are so common and plentiful at this mine, but that help brighten up a collection; like lilac colored lepidolite, the combination of deep green manganapatitie and red massive garnet, and spodumene, much of which is changed to green and chocolate-brown pinite, and pink kunzite."

Seaman (1947) provides some additional commentary:

"The opening up of the Schoonmaker mine occurred in July, 1933, and some truly fine tourmalines could be collected from the first material thrown out from near the surface. Tourmalines in five colors were easily collected ranging from green through yellow to purple, blue, and black either from one end of a crystal to the other end or perhaps in a series of different colored crystals in parallel position with each other. Much of this material was quickly covered up so I feel that if one could get into the center of this dump some fine tourmalines could still be found.

"On November 11, 1934, in company with the editor of this magazine, the locality was visited again. Many excellent minerals were available. Lepidolite was still quite common as well as large, lath shaped, portions of spodumene crystals cutting blue cleavelandite, many crystals coming together at a point in a V-termination. One such specimen had a perfectly terminated spodumene crystal attached to it, about an inch long. A small one-half inch long bicolored pink and green tourmaline crystal with pink interior and outer edge green, like a water¬melon, was picked up from the dump of the Schoonmaker mine. A small perfectly terminated manganapatite crystal with black tourmaline and almandite garnets and yellow beryl as associated minerals was secured."

When closed after WWII, Schooner (1947) gave this description of the site:

"As some collectors undoubtedly know, the Collins Hill locality is completely inactive with the Strickland Feldspar Quarry submerged in a veritable sea of bluish-green water and the Schoonmaker Mica Mine looking as though it had been deserted for a decade! All of the buildings are still standing and locked at the latter working, but the vicinity of the Strickland has surrendered everything that could possibly aid in relieving the lumber shortage. The big dump still provides some interesting minerals, but these are naturally of the rarer less colorful, and more readily overlooked species. I have had my best luck in finding the relatively uncommon phosphates of the lithiophilite series of alteration products. In addition to these I have also found several specimens containing crystallized uraninite with an occasional incrustation of reddish-orange gummite."

When the golf course was built in the 1990s the dump was removed and the flooded shaft filled in with rocks and soil. Collecting is no longer allowed or possible in any case.

Mineral List

Actinolite Albite var: Cleavelandite Almandine Annite Aragonite Bertrandite Beryl var: Aquamarine var: Heliodor var: Morganite

Calcite Cordierite Diopside Elbaite Fluorapatite Fluorite Grossular 'Gummite' Lepidolite Lithiophilite

Microcline Montebrasite Muscovite Pickeringite 'Pinite' Pyrite Quartz var: Rock Crystal var: Smoky Quartz Rhodochrosite

'Scapolite' ? Schorl Sphalerite Spodumene 'Tourmaline var: Rubellite' 'var: Verdelite' Uraninite Xenotime-(Y) Zoisite

39 entries listed. 28 valid minerals.

References

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