Corundum and grossular locality, Barkhamsted, Litchfield County, Connecticut, USAi
| Regional Level Types | |
|---|---|
| Corundum and grossular locality | - not defined - |
| Barkhamsted | - not defined - |
| Litchfield County | County |
| Connecticut | State |
| USA | Country |
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Latitude & Longitude (WGS84):
41° 54' 37'' North , 72° 57' 15'' West (est.)
Estimate based on other nearby localities or region boundaries.
Margin of Error:
~0km
KΓΆppen climate type:
Mindat Locality ID:
266401
Long-form identifier:
1:2:266401:2
GUID (UUID V4):
b649da6b-baa6-46c9-9f63-0ee87d330c37
Emerson (1902) reports receiving corundum-rich and calc-silicate rocks from a resident of the Pleasant Valley section of town. He does not say that the rocks were actually from the donor's property, the address is not provided, and the rocks could be from 2 different localities, but the title of the article states they are from Barkhamsted. The calc-silicate consists of well-formed grossular, with graphite, calcite, wollastonite (possibly actually tremolite, which is far more common in this state), and diopside. The corundum-rich rock is described as a pure bed about 6 cm thick, colored dark blue with irregular pistachio green patches, with minor included kyanite.
Emerson (1902) reported the local schistose rocks to be rich in almandine, kyanite, sillimanite magnetite, and staurolite.
Schairer (1931) and Januzzi (1959) allude to Emerson's report, with no new details.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| β Almandine Formula: Fe2+3Al2(SiO4)3 Colour: red Description: Garnet porphyroblasts in the local "coarse schist", 2-5 mm. Nearly all schist hosted garnet in Connecticut, especially associated with staurolite as noted by Emerson, is almandine. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Calcite Formula: CaCO3 Habit: massive Description: Matrix for grossular, diopside, and graphite calc-silicate rock described by Emerson. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Corundum Formula: Al2O3 Habit: massive granular Colour: dark blue to pistachio green Description: In a nearly pure bed with kyanite and graphite 6 cm thick. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Diopside Formula: CaMgSi2O6 Habit: anhedral Description: "Large anhedra" in calc-silicate rock including grossular, calcite, graphite. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Graphite Formula: C Habit: platy Description: Masses and platy crystals associated with calcite and grossular in a calc-silicate rock. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| βͺ Grossular Formula: Ca3Al2(SiO4)3 Habit: dodecahedral Colour: colorless to pale honey-yellow Description: In a contiguous layer of crystals to >2 inches in calc-silicate rock with interpenetrating graphite, diopside, calcite. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Kyanite Formula: Al2(SiO4)O Habit: elongated prismatic blades Colour: black Description: As porphyroblasts in the local schist ("crisscrossed blades an inch wide and two inches long") and embedded in the corundum layer. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Magnetite Formula: Fe2+Fe3+2O4 Habit: grains Description: "Large grains" embedded in sillimanite-rich layers a few cm thick. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Quartz Formula: SiO2 Habit: granular Description: A minor component of the calc-silicate rock hosting grossular, graphite, diopside. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Sillimanite Formula: Al2(SiO4)O Habit: fibrous Description: In "inch thick" nearly pure layers with magnetite. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Staurolite Formula: Fe2+2Al9Si4O23(OH) Colour: dark reddish brown Description: As porphyroblasts "an inch across" with almandine in the local "coarse schist". Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
| β Wollastonite ? Formula: Ca3(Si3O9) Habit: feathery columnar aggregates Description: A component of the calc-silicate rock hosting grossular, calcite, diopside, graphite. Visual ID, wollastonite is rare in Connecticut and the mineral may be the much more common tremolite instead. Reference: Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| β | Graphite | 1.CB.05a | C |
| Group 4 - Oxides and Hydroxides | |||
| β | Corundum | 4.CB.05 | Al2O3 |
| β | Magnetite | 4.BB.05 | Fe2+Fe3+2O4 |
| β | Quartz | 4.DA.05 | SiO2 |
| Group 5 - Nitrates and Carbonates | |||
| β | Calcite | 5.AB.05 | CaCO3 |
| Group 9 - Silicates | |||
| β | Almandine | 9.AD.25 | Fe2+3Al2(SiO4)3 |
| β | Diopside | 9.DA.15 | CaMgSi2O6 |
| β | Grossular | 9.AD.25 | Ca3Al2(SiO4)3 |
| β | Kyanite | 9.AF.15 | Al2(SiO4)O |
| β | Sillimanite | 9.AF.05 | Al2(SiO4)O |
| β | Staurolite | 9.AF.30 | Fe2+2Al9Si4O23(OH) |
| β | Wollastonite ? | 9.DG.05 | Ca3(Si3O9) |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | β Staurolite | Fe22+Al9Si4O23(OH) |
| C | Carbon | |
| C | β Graphite | C |
| C | β Calcite | CaCO3 |
| O | Oxygen | |
| O | β Grossular | Ca3Al2(SiO4)3 |
| O | β Almandine | Fe32+Al2(SiO4)3 |
| O | β Sillimanite | Al2(SiO4)O |
| O | β Kyanite | Al2(SiO4)O |
| O | β Corundum | Al2O3 |
| O | β Staurolite | Fe22+Al9Si4O23(OH) |
| O | β Quartz | SiO2 |
| O | β Magnetite | Fe2+Fe23+O4 |
| O | β Diopside | CaMgSi2O6 |
| O | β Calcite | CaCO3 |
| O | β Wollastonite | Ca3(Si3O9) |
| Mg | Magnesium | |
| Mg | β Diopside | CaMgSi2O6 |
| Al | Aluminium | |
| Al | β Grossular | Ca3Al2(SiO4)3 |
| Al | β Almandine | Fe32+Al2(SiO4)3 |
| Al | β Sillimanite | Al2(SiO4)O |
| Al | β Kyanite | Al2(SiO4)O |
| Al | β Corundum | Al2O3 |
| Al | β Staurolite | Fe22+Al9Si4O23(OH) |
| Si | Silicon | |
| Si | β Grossular | Ca3Al2(SiO4)3 |
| Si | β Almandine | Fe32+Al2(SiO4)3 |
| Si | β Sillimanite | Al2(SiO4)O |
| Si | β Kyanite | Al2(SiO4)O |
| Si | β Staurolite | Fe22+Al9Si4O23(OH) |
| Si | β Quartz | SiO2 |
| Si | β Diopside | CaMgSi2O6 |
| Si | β Wollastonite | Ca3(Si3O9) |
| Ca | Calcium | |
| Ca | β Grossular | Ca3Al2(SiO4)3 |
| Ca | β Diopside | CaMgSi2O6 |
| Ca | β Calcite | CaCO3 |
| Ca | β Wollastonite | Ca3(Si3O9) |
| Fe | Iron | |
| Fe | β Almandine | Fe32+Al2(SiO4)3 |
| Fe | β Staurolite | Fe22+Al9Si4O23(OH) |
| Fe | β Magnetite | Fe2+Fe23+O4 |
References
Sort by
Year (asc) Year (desc) Author (A-Z) Author (Z-A)Emerson, B. K. (1902), Note on Corundum and a Graphitic Essonite, from Barkhamsted, Connecticut. American Journal of Science: s. 4, 14: 234-6.
Schairer, J. F. (1931), The Minerals of Connecticut. State Geological and Natural History Survey Bulletin 51.
Januzzi, Ronald E. (1959), The Minerals of Western Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut.
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Piedmontia DomainDomain
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Corundum and grossular locality, Barkhamsted, Litchfield County, Connecticut, USA