Pegmatite quarry and ultramafic rock, Harwinton, Litchfield County, Connecticut, USAi
| Regional Level Types | |
|---|---|
| Pegmatite quarry and ultramafic rock | Quarry |
| Harwinton | - not defined - |
| Litchfield County | County |
| Connecticut | State |
| USA | Country |
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Latitude & Longitude (WGS84):
41° 45' 58'' North , 73° 5' 12'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Northwest Harwinton | 3,252 (2017) | 1.3km |
| Torrington | 34,906 (2017) | 4.8km |
| West Torrington | 36,000 (2017) | 7.5km |
| Litchfield | 1,215 (2017) | 8.7km |
| Thomaston | 1,910 (2017) | 10.3km |
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 |
|---|---|---|
| Bristol Gem & Mineral Club | Bristol, Connecticut | 16km |
| Lapidary and Mineral Society of Central Connecticut | Meriden, Connecticut | 34km |
A small quarry in a granite pegmatite (Nonewaug granite outlier) along the power line right-of-way just south of state Route 118 and west of Hill Road. Nothing has apparently been written about it, but specimens occasionally show up in old collections.
Along the SE side of the pegmatite is a small body of altered ultramafic rock, with another one situated about 300 m to the SW (Martin, 1970). Given their proximity to the pegmatite quarry, one or both of these may be the source of various specimens in collections labeled only as "Harwinton", though there are other such bodies north of state Route 118 also. These are green to olive, massive Ca/Mg-silicate assemblage from alteration of an ultramafic rock body containing minerals like green (Cr-rich) and white fibrous tremolite, green (Cr-rich) grossular (assumed), diopside, actinolite, epidote, calcite, quartz, magnetite, etc. They match the description in Martin (1970).
Yale Peabody Museum has a specimen of "halotrichite" with "Hill Road" as the locality. An SEM-EDS analysis of a similar sample in another collection (again labelled only as "Harwinton") shows it to be pickeringite, the Mg end member of the visually indistinguishable halotrichite-pickeringite series. It may have formed from weathering of a Mg-rich ultramafic body. Given that Hill Road is very long but otherwise has very little rock exposure along it, the ultramafic bodies near its north end appear to be the likely source.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Actinolite Formula: ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 Habit: acicular Colour: dark green Description: Layers of bedded needles with coarse-grained chrome-tremolite in altered ultramafic rock. |
| ⓘ Albite Formula: Na(AlSi3O8) References: |
| ⓘ Beryl Formula: Be3Al2(Si6O18) References: |
| ⓘ Calcite Formula: CaCO3 Habit: massive Colour: white Description: Massive material in altered ultramafic rock. |
| ⓘ Diopside Formula: CaMgSi2O6 Habit: massive Colour: Pale green-brown Description: Part of altered ultramafic rock assemblage. |
| ⓘ Epidote Formula: (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) Habit: subhedral elongated prisms to massive Colour: olive green Description: Part of ultramafic rock assemblage. |
| ⓘ Grossular Formula: Ca3Al2(SiO4)3 Habit: granular Colour: emerald green Description: Tiny but bright green grains in ultramafic rock assemblage, assumed to be Cr-rich grossular rather than the much rarer uvarovite. |
| ⓘ Halotrichite ? Formula: FeAl2(SO4)4 · 22H2O Habit: fibrous Colour: off-white to pale yellow Description: Spongy mass of tiny fibrous crystals with included weathered-out mica flakes. May be all or in part pickeringite. References: |
| ⓘ Magnetite Formula: Fe2+Fe3+2O4 Habit: granular Colour: black Description: Tiny grains in altered ultramafic rock. |
| ⓘ Microcline Formula: K(AlSi3O8) References: |
| ⓘ Muscovite Formula: KAl2(AlSi3O10)(OH)2 References: |
| ⓘ Pickeringite Formula: MgAl2(SO4)4 · 22H2O Habit: fibrous Colour: pale yellow Description: Spongy mass of tiny fibrous crystals with included weathered-out mica flakes. |
| ⓘ Quartz Formula: SiO2 Colour: smoky to colorless Description: Major component of the pegmatite, mostly massive but euhedral pocket crystals are known. Minor constituent in altered ultramafic rock. |
| ⓘ Schorl Formula: NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) References: |
| ✪ Tremolite Formula: ◻Ca2Mg5(Si8O22)(OH)2 Habit: massive to subhedral prismatic, acicular, fibrous Colour: emerald green, white Description: Coarse-grained green (Cr-rich) material with beds of white finer-grained, aciular to fibrous massive crystals in altered ultramafic rock. |
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 5 - Nitrates and Carbonates | |||
| ⓘ | Calcite | 5.AB.05 | CaCO3 |
| Group 7 - Sulphates, Chromates, Molybdates and Tungstates | |||
| ⓘ | Halotrichite ? | 7.CB.85 | FeAl2(SO4)4 · 22H2O |
| ⓘ | Pickeringite | 7.CB.85 | MgAl2(SO4)4 · 22H2O |
| Group 9 - Silicates | |||
| ⓘ | Grossular | 9.AD.25 | Ca3Al2(SiO4)3 |
| ⓘ | Epidote | 9.BG.05a | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| ⓘ | Beryl | 9.CJ.05 | Be3Al2(Si6O18) |
| ⓘ | Schorl | 9.CK.05 | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
| ⓘ | Diopside | 9.DA.15 | CaMgSi2O6 |
| ⓘ | Actinolite | 9.DE.10 | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| ⓘ | Tremolite | 9.DE.10 | ◻Ca2Mg5(Si8O22)(OH)2 |
| ⓘ | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
| ⓘ | Microcline | 9.FA.30 | K(AlSi3O8) |
| ⓘ | Albite | 9.FA.35 | Na(AlSi3O8) |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| H | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| H | ⓘ Halotrichite | FeAl2(SO4)4 · 22H2O |
| H | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| H | ⓘ Pickeringite | MgAl2(SO4)4 · 22H2O |
| H | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| H | ⓘ Tremolite | ◻Ca2Mg5(Si8O22)(OH)2 |
| Be | Beryllium | |
| Be | ⓘ Beryl | Be3Al2(Si6O18) |
| B | Boron | |
| B | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| C | Carbon | |
| C | ⓘ Calcite | CaCO3 |
| O | Oxygen | |
| O | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| O | ⓘ Albite | Na(AlSi3O8) |
| O | ⓘ Beryl | Be3Al2(Si6O18) |
| O | ⓘ Calcite | CaCO3 |
| O | ⓘ Diopside | CaMgSi2O6 |
| O | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| O | ⓘ Grossular | Ca3Al2(SiO4)3 |
| O | ⓘ Halotrichite | FeAl2(SO4)4 · 22H2O |
| O | ⓘ Magnetite | Fe2+Fe23+O4 |
| O | ⓘ Microcline | K(AlSi3O8) |
| O | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| O | ⓘ Pickeringite | MgAl2(SO4)4 · 22H2O |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| O | ⓘ Tremolite | ◻Ca2Mg5(Si8O22)(OH)2 |
| Na | Sodium | |
| Na | ⓘ Albite | Na(AlSi3O8) |
| Na | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| Mg | Magnesium | |
| Mg | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| Mg | ⓘ Diopside | CaMgSi2O6 |
| Mg | ⓘ Pickeringite | MgAl2(SO4)4 · 22H2O |
| Mg | ⓘ Tremolite | ◻Ca2Mg5(Si8O22)(OH)2 |
| Al | Aluminium | |
| Al | ⓘ Albite | Na(AlSi3O8) |
| Al | ⓘ Beryl | Be3Al2(Si6O18) |
| Al | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Al | ⓘ Grossular | Ca3Al2(SiO4)3 |
| Al | ⓘ Halotrichite | FeAl2(SO4)4 · 22H2O |
| Al | ⓘ Microcline | K(AlSi3O8) |
| Al | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| Al | ⓘ Pickeringite | MgAl2(SO4)4 · 22H2O |
| Al | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| Si | Silicon | |
| Si | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| Si | ⓘ Albite | Na(AlSi3O8) |
| Si | ⓘ Beryl | Be3Al2(Si6O18) |
| Si | ⓘ Diopside | CaMgSi2O6 |
| Si | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Si | ⓘ Grossular | Ca3Al2(SiO4)3 |
| Si | ⓘ Microcline | K(AlSi3O8) |
| Si | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| Si | ⓘ Quartz | SiO2 |
| Si | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
| Si | ⓘ Tremolite | ◻Ca2Mg5(Si8O22)(OH)2 |
| S | Sulfur | |
| S | ⓘ Halotrichite | FeAl2(SO4)4 · 22H2O |
| S | ⓘ Pickeringite | MgAl2(SO4)4 · 22H2O |
| K | Potassium | |
| K | ⓘ Microcline | K(AlSi3O8) |
| K | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| Ca | Calcium | |
| Ca | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| Ca | ⓘ Calcite | CaCO3 |
| Ca | ⓘ Diopside | CaMgSi2O6 |
| Ca | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Ca | ⓘ Grossular | Ca3Al2(SiO4)3 |
| Ca | ⓘ Tremolite | ◻Ca2Mg5(Si8O22)(OH)2 |
| Fe | Iron | |
| Fe | ⓘ Actinolite | ◻Ca2(Mg4.5-2.5Fe0.5-2.5)Si8O22(OH)2 |
| Fe | ⓘ Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Fe | ⓘ Halotrichite | FeAl2(SO4)4 · 22H2O |
| Fe | ⓘ Magnetite | Fe2+Fe23+O4 |
| Fe | ⓘ Schorl | NaFe32+Al6(Si6O18)(BO3)3(OH)3(OH) |
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Piedmontia DomainDomain
- Taconic ArcVolcanic Arc
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Pegmatite quarry and ultramafic rock, Harwinton, Litchfield County, Connecticut, USA