Almandine from
Strickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA
| Locality type: | Quarry | |
| Classification | ||
|---|---|---|
| Species: | Almandine | |
| Formula: | Fe32+Al2(SiO4)3 | |
| Comments: | As generally small crystals in the outer zones of the pegmatite, but also massive concentrations mixed with fluorapatite, zinnwaldite/masutomilite, elbaite and columbite-(Fe) in cleavelandite. Gemmy crystals in this assemblage confirmed using Raman spectroscopy typically partially replaced by waxy yellow fine-grained muscovite (also confirmed by Raman). Also, in the host metamorphic rocks as a component of "coticule" rock. This rock is described by Lundgren (1979) (the bedrock quadrangle report for Haddam - QR37) as a "bedded garnet-quartz rock (coticule) that consists of thin layers (millimeter-to-centimeter thick) of fine-grained spessartine-quartz granofels. Plagioclase, biotite [annite], and hornblende are present in some layers, but the rocks are essentially aggregates of very small (less than 0.05-0.1 mm) garnet crystals and quartz." Though coticule from around New England has been described as containing spessartine, the particular garnet species here was recently confirmed as almandine using Raman spectroscopy by Paul Bartholomew at U. New Haven. Schooner describes coticule as "a granular pink spessartine rock...can be found in many parts of the area, as in the vicinity of the Strickland quarry. Veins are usually thin and sinuous, but may reach a thickness of several inches. Such material is attractive in large polished slabs." | |
| Habit: | trapezohedral, granular | |
| Colour: | maroon to red-brown | |
| Abundance at site: | Common | |
| Confirmation | ||
| Validity: | Confirmed | |
| Confirmation Methods: | Raman Spectroscopy | |
| Associated Minerals Based on Photo Data: | ||
| Albite | 21 | |
| - var Cleavelandite | 9 | |
| Fluorapatite | 10 | |
| Quartz | 8 | |
| Cookeite | 5 | |
| Elbaite | 5 | |
| Zinnwaldite | 3 | |
| Columbite-(Fe) | 2 | |
| Chlorite Group | 2 | |
| Rutile | 2 | |
| Meta-autunite | 1 | |
| Opal | 1 | |
| - var Opal-AN | 1 | |
| Zircon | 1 | |
| Beryl | 1 | |
| Muscovite | 1 | |
| Microcline | 1 | |
| Data | ||
| Mineral Data: | Click here to view Almandine data | |
| Locality Data: | Click here to view Strickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA | |
| Photo Gallery | View Gallery (12 photos) | |
| Data Identifiers | ||
| Mindat Occurrence Record ID: | 37137 | |
| Long-form Identifier: | 1:3:37137:9 | |
| GUID (UUID V4): | 0 | |
| Nearest other occurrences of Almandine | ||
| 0.1km (0.1 miles) | ⓘSchoonmaker Mine, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA | |
| 0.8km (0.5 miles) | ⓘHale-Walker prospects, Collins Hill, Portland, Middlesex County, Connecticut, USA | |
| 0.8km (0.5 miles) | ⓘPegmatite prospects, Collins Hill, Portland, Middlesex County, Connecticut, USA | |
| 1.6km (1.0 miles) | ⓘPelton's Quarry, Portland, Middlesex County, Connecticut, USA | |
| 3.0km (1.8 miles) | ⓘWalden Gem Quarry, Portland, Middlesex County, Connecticut, USA | |
| 3.4km (2.1 miles) | ⓘBordonaro Quarry, Portland, Middlesex County, Connecticut, USA | |
| 3.8km (2.3 miles) | ⓘCase Quarry No. 2, Case Quarries, Portland, Middlesex County, Connecticut, USA | |
| 3.8km (2.3 miles) | ⓘState Forest Quarry No. 2, Cobalt, East Hampton, Middlesex County, Connecticut, USA | |
| 3.8km (2.3 miles) | ⓘCase Quarry No. 1, Case Quarries, Portland, Middlesex County, Connecticut, USA | |
| 3.8km (2.3 miles) | ⓘCase Quarries, Portland, Middlesex County, Connecticut, USA | |
| References | ||
Strickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA