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Unnamed amphibole-tourmaline-magnetite locality, Haddam Neck, Haddam, Middlesex County, Connecticut, USAi
| Regional Level Types | |
|---|---|
| Unnamed amphibole-tourmaline-magnetite locality | - not defined - |
| Haddam Neck | - not defined - |
| Haddam | Town |
| Middlesex County | County |
| Connecticut | State |
| USA | Country |
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Latitude & Longitude (WGS84):
41° 30' 38'' North , 72° 32' 5'' West
Latitude & Longitude (decimal):
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Higganum | 1,698(2017) | 2.4km |
| Moodus | 1,413(2017) | 7.1km |
| East Hampton | 2,691(2017) | 7.7km |
| East Haddam | 9,042(2017) | 8.9km |
| Lake Pocotopaug | 3,436(2017) | 10.0km |
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Lapidary and Mineral Society of Central Connecticut | Meriden, Connecticut | 23km |
| Bristol Gem & Mineral Club | Bristol, Connecticut | 39km |
| New Haven Mineral Club | New Haven, Connecticut | 40km |
Schooner (circa 1985) describes magnetite from "Chlorite layers...in the cliffs overlooking the Connecticut River on the Rohrbach property above Rock Landing in Haddam Neck. Very sharp octahedrons, to 1/2 inch, have been collected there, and in the same situation on a hillside south of Clarkhurst Road."
He also notes: "Gedrite, anthophyllite, and cummingtonite are seen in outcrops between Rock Landing Road and Clarkhurst Road, especially in cliffs above the river." These cliffs are underlain by the upper Middletown Formation metavolcanics, which is orthoamphibole rich.
Field observations during 2015 along the outcrops of Upper Middletown Formation in Dudley Seymour State Park, contiguous with the cliff outcrops described by Schooner, revealed abundant dark orthoamphibole crystals (described as gedrite or anthophyllite in various publications) to several cm as flat sprays parallel with the foliation; black tourmaline as concentrations in quartz veins, in small pegmatites, and as isolated crystals up to 10 cm lying parallel with the foliation; scattered magnetite crystals in gray gneiss (no chlorite-rich layers were obvious); and rare boudins containing cordierite (all very typical of this formation).
Coordinates are where the Upper Middletown Formation crosses Clarkhurst Road in the park. Outcrops are mostly SE of this point all along the SW-facing slope.
Select Mineral List Type
StandardDetailedGalleryStrunzChemical ElementsDetailed Mineral List:
| ⓘAlbite Formula:Na(AlSi3O8) Habit: anhedral Colour: white Description: As a coarse-grained component of pegmatites. References: |
| ✪Anthophyllite Formula:◻{Mg2}{Mg5}(Si8O22)(OH)2 Habit: elongated, flattened prisms Colour: black to dark green Description: As feathery crystal groups aligned with foliation, crystals typically up to 6 cm long. TEM-EDS analyses were conducted on typical amphiboles in the Middletown Formation. These all proved to be anthophyllite. |
| ⓘ'Chlorite Group' |
| ⓘCordierite Formula:(Mg,Fe)2Al3(AlSi5O18) Habit: massive granular Colour: grayish purple Description: Seen in the field as a granular component in a few approximately 15 cm boudins. References: |
| ⓘ Formula:◻{Mg2}{Mg5}(Si8O22)(OH)2 Description: Presence speculative. Dimorphous with anthophyllite so TEM-EDS analyses with selected area electron diffraction (SAED) to show structure was conducted on typical amphiboles in the Middletown Formation. These all proved to be anthophyllite. |
| ⓘGedrite ? Formula:◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 Description: TEM-EDS analyses on typical amphiboles in the Middletown Formation, even ones described as gedrite by the author of the Haddam bedrock geological quadrangle map (Lundgren, 1979) have all proved to be anthophyllite under the latest IMA nomenclature. |
| ⓘMagnetite Formula:Fe2+Fe3+2O4 Habit: octahedral Description: Sharp crystals to 0.5 inch in chlorite schist, others scattered in gray gneiss. |
| ⓘMicrocline Formula:K(AlSi3O8) Habit: anhedral Colour: tan to pink Description: As a coarse-grained component in pegmatites. References: |
| ⓘQuartz Formula:SiO2 Habit: massive Colour: white to gray Description: In isolated veins with or without tourmaline, as a component of pegmatites. References: |
| ⓘ'Tourmaline' Formula:AD3G6(T6O18)(BO3)3X3Z Habit: stout to acicular prisms Colour: black Description: As concentrations in quartz veins (typically acicular to granular) or in layers in gray gneiss, as small groups or isolated stout crystals some doubly-terminated to around 8-9 cm. Rarely in pegmatite. References: |
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Magnetite | 4.BB.05 | Fe2+Fe3+2O4 |
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 9 - Silicates | |||
| ⓘ | Cordierite | 9.CJ.10 | (Mg,Fe)2Al3(AlSi5O18) |
| ⓘ | Anthophyllite | 9.DD.05 | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| ⓘ | Gedrite ? | 9.DD.05 | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| ⓘ | Cummingtonite ? | 9.DE.05 | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| ⓘ | Microcline | 9.FA.30 | K(AlSi3O8) |
| ⓘ | Albite | 9.FA.35 | Na(AlSi3O8) |
| Unclassified | |||
| ⓘ | 'Chlorite Group' | - | |
| ⓘ | 'Tourmaline' | - | AD3G6(T6O18)(BO3)3X3Z |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘAnthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| H | ⓘCummingtonite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| H | ⓘGedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| B | Boron | |
| B | ⓘTourmaline | AD3G6(T6O18)(BO3)3X3Z |
| O | Oxygen | |
| O | ⓘAlbite | Na(AlSi3O8) |
| O | ⓘAnthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| O | ⓘCordierite | (Mg,Fe)2Al3(AlSi5O18) |
| O | ⓘCummingtonite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| O | ⓘGedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| O | ⓘMagnetite | Fe2+Fe23+O4 |
| O | ⓘMicrocline | K(AlSi3O8) |
| O | ⓘQuartz | SiO2 |
| O | ⓘTourmaline | AD3G6(T6O18)(BO3)3X3Z |
| Na | Sodium | |
| Na | ⓘAlbite | Na(AlSi3O8) |
| Mg | Magnesium | |
| Mg | ⓘAnthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| Mg | ⓘCordierite | (Mg,Fe)2Al3(AlSi5O18) |
| Mg | ⓘCummingtonite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| Mg | ⓘGedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| Al | Aluminium | |
| Al | ⓘAlbite | Na(AlSi3O8) |
| Al | ⓘCordierite | (Mg,Fe)2Al3(AlSi5O18) |
| Al | ⓘGedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| Al | ⓘMicrocline | K(AlSi3O8) |
| Si | Silicon | |
| Si | ⓘAlbite | Na(AlSi3O8) |
| Si | ⓘAnthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| Si | ⓘCordierite | (Mg,Fe)2Al3(AlSi5O18) |
| Si | ⓘCummingtonite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| Si | ⓘGedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| Si | ⓘMicrocline | K(AlSi3O8) |
| Si | ⓘQuartz | SiO2 |
| K | Potassium | |
| K | ⓘMicrocline | K(AlSi3O8) |
| Fe | Iron | |
| Fe | ⓘCordierite | (Mg,Fe)2Al3(AlSi5O18) |
| Fe | ⓘMagnetite | Fe2+Fe23+O4 |
Other Regions, Features and Areas containing this locality
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References
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Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2025, except where stated. Most political location boundaries are© OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 byJolyon Ralph.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844.doi:10.2138/am-2024-9486.
Privacy Policy -Terms & Conditions -Contact Us / DMCA issues -Report a bug/vulnerabilityCurrent server date and time: November 29, 2025 00:18:15 Page updated: August 28, 2025 22:16:24