Garnet prospect, Middle Haddam, East Hampton (Chatham), Middlesex Co., Connecticut, USAi
|Regional Level Types|
|Middle Haddam||- not defined -|
|East Hampton (Chatham)||- not defined -|
|Latitude & Longitude (WGS84):||41° 33' 8'' North , 72° 32' 53'' West|
|Latitude & Longitude (decimal):||41.55222,-72.54806|
|Köppen climate type:||Dfa : Hot-summer humid continental climate|
This is one of these small places that seems to get more mention than it warrants.
The first one is by Taylor (1824):
They are found about eighty rods east of the Landing. They occur in vast abundance, and are from one to two inches diameter.
Schooner (1958) mentions it briefly in a few places:
Large reddish [staurolite] crystals, unfortunately rough and of very poor quality, can be found in the ledges near the old garnet mine in Middle Haddam....
Last worked in 19th Century (?).
A resident and collector has described it as beside the road and not much more than a small prospect pit. Taylor's directions place it in a depression on the south side of Schoolhouse Road with no rock now exposed. Area is residential private property. The garnet is almost certainly the species almandine, as that is by far the most common schist-hosted garnet in Connecticut.
Select Mineral List TypeStandard Detailed Strunz Dana Chemical Elements
Detailed Mineral List:
Description: Not tested, but species probably almandine, as most schist-hosted garnets in Connecticut have proven to be. Crystals to 1-2 inches.
Reference: Taylor, Steuben. (1824), Miscellaneous localities of minerals. American Journal of Science: s. 1, 7: 253-4.; Schairer, J. F. (1931), The Minerals of Connecticut. State Geological and Natural History Survey Bulletin 51.
Description: Could be the brown mineral Schooner (1958) says looks like anthophyllite.
Reference: Harvard Mineralogical Museum
| ⓘ Staurolite|
Reference: Schooner, Richard. (1958): The Mineralogy of the Portland-East Hampton-Middletown-Haddam Area in Connecticut (With a few notes on Glastonbury and Marlborough).
List of minerals arranged by Strunz 10th Edition classification
|Group 9 - Silicates|
List of minerals arranged by Dana 8th Edition classification
|Group 51 - NESOSILICATES Insular SiO4 Groups Only|
|Insular SiO4 Groups Only with cations in  and > coordination|
|Group 52 - NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O|
|Insular SiO4 Groups and O, OH, F, and H2O with cations in  and > coordination|
|Group 66 - INOSILICATES Double-Width,Unbranched Chains,(W=2)|
|Amphiboles - Mg-Fe-Mn-Li subgroup|
List of minerals for each chemical element
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
|Metavolcanic member [of Collins Hill Formation]|
Age: Ordovician (443.8 - 470 Ma)
Stratigraphic Name: Collins Hill Formation
Description: Ranges from mafic to felsic, from dark layered amphibolite and hornblende schist, locally with garnet or epidote, to light-gray (in places purplish), laminated gneiss, composed of quartz, oligoclase, and biotite, in which some layers contain garnet (generally manganiferous) and hornblende or cummingtonite.
Comments: Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Bronson Hill Anticlinorium; Brimfield Schist and equivalent formations (includes Collins Hill Formation) (Upper? and Middle Ordovician). Original map source: Connecticut Geological and Natural History Survey, DEP, in cooperation with the U.S. Geological Survey, 2000, Bedrock Geology of Connecticut, shapefile, scale 1:50,000
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.