Hewitt Gem Quarry (Herb's Gem Quarry; Sawmill Quarry), Haddam, Middlesex Co., Connecticut, USA
|Latitude & Longitude (WGS84):||41° 27' 10'' North , 72° 30' 38'' West|
|Latitude & Longitude (decimal):||41.45278,-72.51056|
|Köppen climate type:||Cfa : Humid subtropical climate|
Herb Hewitt’s gem mine was a popular collecting place during the 1960s and 1970s and since 2013 has become one again. It is a group of small pegmatite quarries that boasted mineralogy and specimen quality similar to the famous Gillette Quarry across the river in Haddam Neck. Both are zoned pegmatites with cleavelandite and lithium enrichment and feature beryls with clear to pale green cores and pink overgrowths among other minerals.
Major activity apparently began around 1960 because it is mentioned briefly in Schooner (1961) but not at all in Schooner (1958). However, there was activity before then, as Williams (circa 1945) mentions that "At a Feldspar prospect on land of a Mr. Elly near Turkeyhill Road, green tourmaline in muscovite, lepidolite, smoky quartz, fine transparent crystals." Indeed, according to town records, the quarry was once owned by William Ely, and was sold to Ernest McNutt, by his daughter Alice Ely, in 1944. Ernest McNutt rented the quarry to the Hewitts for some years then sold it to them on March 28, 1960.
This is largely substantiated by Gregory (1966):
In August, 1961, Herbert Hewitt leased the land for mining and prospecting. He found that the dike of pegmatite extended underground quite some distance to the northeast. Mr. Hewitt and his brother have been working the quarry for the last four years, looking for strategic minerals needed for defense and the space age.
In the 1940s, apparently Mr. Ely owned it but Mr. DeLucca worked it.
To attract rockhounds to this fee collecting site, Herb Hewitt published advertisement fliers. The color ad featured a pile of multi-colored gem beryl rough, much of which was actually from the Roebling Quarry in Upper Merryall, which the Hewitts also worked.
The first technical description of it comes from Barton and Goldsmith (1968):
The quarry area (fig. 32) is underlain by intercalated biotite and hornblende schists and gneisses interrupted by numerous, small pegmatite dikes and sills many of which have been prospected for gem beryl. The country rocks strike approximately north-south and schistosity and banding in the rocks range in dip from vertical to 45° E. The Sawmill Quarry is the only pegmatite on the hill which has been developed.
At the Sawmill Quarry a small sill has been opened by four small prospect pits. The sill strikes N 3° W and dips 45° to 86° E with the foliation of the enclosing rocks. It is exposed for 400 feet along strike and is about 10 feet thick. Because of its eastward dip it has not been explored to any extent downdip, where it runs beneath rising ground forming the west slope of Long Hill (also erroneously called Turkey Hill by local prospectors). The pegmatite is zoned, but poorly exposed in the rubble-strewn pits.
The pegmatite was estimated to contain 0.1 to 0.2 percent beryl. Much of it was beautiful blue, green, white, pink, and multicolored doubly terminated gem and specimen crystals. The multicolored beryl has a green core, and white prism faces grading to pink at either end. Crystals averaged about 1 by 3 inches, but were up to 10 inches long.
Taber (1971) described and economically assessed the pegmatite for the Hewitts:
The mineralogy is complex: contained minerals are, feldspar (both plagioclase and orthoclose groups of various colors, including white, tan, green, gray, orange, pink), quartz (including smoky), muscovite, tourmaline (black and golden), beryl (green, aquamarine, yellow, colorless), red garnet, red fluorite, lepidolite, and many others not identified by the writer. Many of the beryls are large enough (over 1 inch diameter) and of gem quality, but fractured by blasting.
No commercial product in volume has been produced from this body so far and the writer has doubts if any will be. However, pegmatites are notoriously unpredictable. In general, the feldspar masses are too small and impure, muscovite books and masses are too small and scattered, and the tenor of the beryl is too low and crystals too small for hand cobbing to upgrade any of these products profitably. However, the variety of minerals and the gem qualities of beryl and tourmaline make the pit a favorite for rockhounds. Also, the pegmatite rock itself has been used as a rock garden stone and a market of a few hundred tons a year can be easily developed.
Herb Hewitt reportedly lived at the quarry during the 1960s and after he passed away in the early 1970s, his brother, Howard, took over trying to promote the quarry for a while and was in his 80s at the time. Howard never worked the quarry as Herb had. The heyday of this locality came to an end when Howard died in 1981. His widow, Emily Hewitt, inherited the land and she used the southern half of the land, #220 Turkey Hill Road, to build the Valley Evangelical Free Church. She sold the northern half, #202 Turkey Hill Road, which contains most if not all of the Hewitt Quarry, to Joseph Mazzotta of Middletown. Aerial photos from 2012 show that the site was abandoned with the pits partially filled in, but most of the dumps remain.
In 2013, James Sipperly introduced Anthony J. Albini and Ray Meyers to owner Joseph Mazzotta. Thereafter, A. J. Albini and Jim Sipperly reviewed the dumps and Joseph Mazzotta started to bulldoze the dumps under A. J. Albini's direction. Since then, several mineral club field trips have been allowed in 2014-15 under owner supervision. As a result, much new material has come to light, including amazonite, several varieties of beryl, masses of deep red to almost black chlorophane, and pockets with smoky quartz. The current owner doesn't want people collecting there (outside of some scheduled field trips) because of hunters in the area.
In 2015, several collectors found the pink, fibrous, lithium-rich muscovite variety "schernikite", first described at the Gillette quarry, in a miarolitic cavity with elbaite to 15 cm, including the "Trick or Treat Pocket" on October 31. In many ways the mineralization at Hewitt is similar to that at Gillette, which is located only 2.7 miles directly north.
31 valid minerals.
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
|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.