|Latitude & Longitude (WGS84):||41° 35' 31'' North , 72° 35' 30'' West|
|Latitude & Longitude (decimal):||41.59222,-72.59167|
|Köppen climate type:||Dfa : Hot-summer humid continental climate|
A former feldspar-mica-Be-Nb-Ta-REE-Sn quarry in granite pegmatite located on the west side and near the summit of Collins Hill, 2½ miles (4 km) NE of Portland. It operated in the Strickland pegmatite along with the separate, underground Schoonmaker or Cramer Mine to the immediate north (a separate locality), though the two were not connected until perhaps the last few years of operations. All the dumps formerly around the quarry except the largest, northernmost one belonged to the Strickland Quarry. The northernmost dump belonged to the Schoonmaker or Cramer Mine. Because most collectors did not realize the northern dump belonged to a different operation, most specimens are referred to as coming from the Strickland Quarry no matter where collected. The difference is largely academic anyway because all the minerals came from the same pegmatite and 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. When a golf course on the site was constructed in the 1990s all of the dumps were removed, and although the flooded quarry pit is still present, collecting is no longer allowed or possible.
Mining supposedly began in the 1840s according to Foye (1922) who stated:
"The quarry was opened as early as 1840. There is a pitcher, bearing in gilt the name of Strickland, now preserved in Wesleyan Museum, which was made from feldspar taken from the quarry at that early date."
If so, it must have been a minor operation as it is not mentioned in Beers' (1884) History of Middlesex County. Ralph Pelton's quarry is mentioned, but this is a separate locality just east of Collins Hill.
Strickland Quarry was operated by F. E. Strickland from 1904 to 1945. It was leased to Eureka Flint & Spar Co., Eureka Mining & Operating Co. or Eureka Mica & Mining Co. Successive operators were F. E. Strickland, George Wilkes, and William Wilkes.
Mostly it was involved in feldspar production before 1937 but was a big mica producer 1930-37, 1942-45, and 1952-53 (from wall zones). It produced 2,000 to 5,000 long tons of feldspar per year and 200 to 400 tons of mica after 1927; also quartz, beryl, and gemstones. Workings include an open cut 300 feet long by 200 feet wide and 140 feet deep. The east cut quarried up to 100 feet deep & connected mines worked 1914-37. Wall zones were mined underground mostly to the north in the 1940s & 1950s.
Cameron (1954) summarized the pegmatite and its zones as follows:
Exposed in east quarry cut and for over 720 ft N-S by 240 ft E-W, 8-60 ft thick. Dips west 30-75 degrees.
Five lithologic zones:
1. quartz-muscovite-plagioclase border zone, 1-8 in. thick
2. plagioclase-quartz-muscovite wall zone, 1-7 ft thick (mica zone – books up to 6 feet!)
3. microcline perthite-graphic granite-quartz-plagioclase intermediate zone 1-22 ft thick (perthite crystals up to 22 ft!)
4. plagioclase (cleavelandite)-quartz intermediate zone up to 45 ft thick
5. quartz core
Mineralization is a pegmatite deposit (Deposit Model code 33; USGS model code 13a; name: Be-Li pegmatites) Late Permian in age, hosted in the Ordovician Collins Hill Formation (= Partridge Formation of New Hampshire). The ore body strikes N-S and dips 35-40/50W at a thickness of 6.71/9 meters, a width of 73 meters and a length of 229 meters, covering an area of 4.8 HA. It is lenticular in shape. The primary mode of origin was magmatic differentiation and secondary was hydrothermal. Primary ore control was bedding. There is moderate wall rock alteration (silicification).
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.
The most diverse mineralogy and miarolitic pockets were mostly found with pale blue to white cleavelandite in zone 4. Descriptions of gem elbaite-rich pockets are found in Bastin (1910), Shannon (1920), Sterrett (1923), and Stearns (1983). Most elbaite is green, but there are concentrically zoned crystals with an olive green exterior, blue intermediate zone, on a core of schorl; classic watermelon tourmaline; and a plethora of pastel shades of gray, pink, green, blue, lavender to colorless. The miarolitic pockets were shattered after initial crystallization as most elbaite crystals are fragmented along with quartz and cleavelandite, with some dissolution of these minerals and so are seldom terminated. If they are terminated they may have a dark blue terminal zone with simple pedion or a very shallow rhombohedral form. Capillary overgrowths cause a schiller effect on many small crystals. Subsequently to pocket collapse, K-rich albite crystallized as separate micro-crystals and as overgrowths on cleavelandite along with quartz as overgrowths on quartz fragments and as tiny microcrystals among the K-rich albite. The latter white to tan colored mineral formed fine-grained masses or druses that host fragmented elbaite and very late forming minerals such as purple fluorapatite, white hydroxylapatite, cookeite, fluorite, pyrite, calcite, chlorite, bertrandite, schernikite, rare zeolites, and masses of fine-grained, secondary, capillary to hairy tourmaline.
The host Collins Hill Formation is a gray, rusty-weathering, medium- to coarse-grained, poorly layered schist, composed of quartz, oligoclase, muscovite, biotite, and garnet, generally graphitic, interlayered with fine-grained two-mica gneiss, especially to the west, and with calc-silicate and amphibolite layers, also rare quartz-almandine [coticule] layers with rare rutile. The schist units contain kyanite, ilmenite, cordierite, pyrrhotite and chalcopyrite in quartz pods and small alpine-cleft type openings with albite (oligoclase), muscovite, pyrite, chlorite, and anatase. The calc-silicate (skarn) units contain a typical Barrovian assemblage of anorthite, actinolite, augite, calcite, diopside, scapolite, grossular, zoisite, vesuvianite, etc. Within this rock, a rare assemblage of wollastonite with gehlenite, spurrite, larnite, grossular, quartz, diopside, vesuvianite, and calcite was documented by Schooner (circa 1985). These and other host rock primary and secondary (gypsum, pickeringite, melanterite, epsomite, sulfur, etc.) minerals are included in the locality species list.
Mindat ArticlesHistory and Mineralology of the Strickland Quarry by Rowan Lytle
119 valid minerals. 15 erroneous literature entries.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Devonian - Silurian|
358.9 - 443.8 Ma
|Paleozoic sedimentary and volcanic rocks|
Age: Paleozoic (358.9 - 443.8 Ma)
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
|Late Ordovician - Middle Ordovician|
443.8 - 470 Ma
|Collins Hill Formation|
Age: Ordovician (443.8 - 470 Ma)
Stratigraphic Name: Collins Hill Formation
Description: ( = Partridge Formation of New Hampshire) - Gray, rusty-weathering, medium- to coarse-grained, poorly layered schist, composed of quartz, oligoclase, muscovite, biotite, and garnet, and commonly staurolite, kyanite, or sillimanite, generally graphitic, interlayered with fine-grained two-mica gneiss, especially to the west, and with calc-silicate and amphibolite layers, also rare quartz-spessartine (coticule) layers.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.