Mill Rock, Hamden, New Haven County, Connecticut, USAi
| Regional Level Types | |
|---|---|
| Mill Rock | Ridge |
| Hamden | - not defined - |
| New Haven County | County |
| Connecticut | State |
| USA | Country |
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Latitude & Longitude (WGS84):
41° 20' 16'' North , 72° 54' 51'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| New Haven | 130,322 (2017) | 3.5km |
| Hamden | 59,847 (2017) | 6.6km |
| North Haven | 24,093 (2017) | 7.5km |
| East Haven | 29,257 (2017) | 7.8km |
| West Haven | 54,927 (2017) | 7.9km |
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 |
|---|---|---|
| New Haven Mineral Club | New Haven, Connecticut | 3km |
| Lapidary and Mineral Society of Central Connecticut | Meriden, Connecticut | 24km |
| Bristol Gem & Mineral Club | Bristol, Connecticut | 37km |
| Danbury Mineralogical Society | Danbury, Connecticut | 45km |
Mindat Locality ID:
47302
Long-form identifier:
mindat:1:2:47302:3
GUID (UUID V4):
16dae675-3f30-4324-8a36-558528c9ad1e
Mill Rock is a diabase intrusive forming a 3/4-mile long, E-W trending ridge cross-cutting the Triassic New Haven Arkose. Mineralization was reported in a small quarry at the west end. Dana (1877) reports on the initial find:
"[Garnets] occur on the line of contact between the trap and the adjoining sandstone, and probably owe their origin to the metamorphic action of the heat of the erupted rock. They are found best in seams and little cavities in the trap, where they are implanted as isolated crystals upon an earlier deposit of quartz crystals. Occasional garnets of indistinct crystalline form but presumably of similar origin occur on the surfaces of the sandstone adjoining; scales of hematite produced by metamorphic action are common on the same surfaces."
Two specimens can be viewed via the Yale Peabody Museum on-line collection at the links below.
Dana (1891) reported veins of prenite and laumontite, with "traces of copper ore" associated with the prehnite vein in a small quarry at the west end of the ridge. Eaton (1927) went there later and managed to find more laumontite.
Dana (1891) mentions another smaller quarry at the eastern corner of Mill Rock Road (coordinates). Eaton (1927) called it the Powder House Quarry and mentions finding prehnite and minor copper mineralization there.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| βͺ Andradite Formula: Ca3Fe3+2(SiO4)3 Habit: modified rhombic dodecahedrons Colour: wine yellow Description: "The Mill Rock garnets have a wine-yellow color, and a brilliant luster. The material available was much too scanty to admit of any chemical examination, but in view of their similarity of form and color, they may safely be referred to the variety topazolite." (Dana, 1877). They are a couple of mm across or less, associated with quartz. |
| βͺ Andradite var. Topazolite Formula: Ca3Fe3+2(SiO4)3 Habit: modified rhombic dodecahedrons Colour: wine yellow Description: "The Mill Rock garnets have a wine-yellow color, and a brilliant luster. The material available was much too scanty to admit of any chemical examination, but in view of their similarity of form and color, they may safely be referred to the variety topazolite." (Dana, 1877). They are a couple of mm across or less, associated with quartz. |
| β Bornite Formula: Cu5FeS4 |
| β Cuprite Formula: Cu2O |
| β Epidote Formula: (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| β Hematite Formula: Fe2O3 Habit: scales Description: In the sandstone near the contact with the diabase. |
| β Hematite var. Specularite Formula: Fe2O3 Description: In the baked arkose below the contact with the diabase. |
| β Laumontite Formula: CaAl2Si4O12 · 4H2O Colour: flesh Description: Massive vein material in vertical fractures. |
| β Malachite Formula: Cu2(CO3)(OH)2 |
| β Prehnite Formula: Ca2Al2Si3O10(OH)2 Habit: botryoidal aggregates |
| β Quartz Formula: SiO2 Colour: white Description: Druses lining cavities associated with andradite. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| β | Bornite | 2.BA.15 | Cu5FeS4 |
| Group 4 - Oxides and Hydroxides | |||
| β | Cuprite | 4.AA.10 | Cu2O |
| β | Hematite | 4.CB.05 | Fe2O3 |
| β | var. Specularite | 4.CB.05 | Fe2O3 |
| β | Quartz | 4.DA.05 | SiO2 |
| Group 5 - Nitrates and Carbonates | |||
| β | Malachite | 5.BA.10 | Cu2(CO3)(OH)2 |
| Group 9 - Silicates | |||
| β | Andradite | 9.AD.25 | Ca3Fe3+2(SiO4)3 |
| β | var. Topazolite | 9.AD.25 | Ca3Fe3+2(SiO4)3 |
| β | Epidote | 9.BG.05a | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| β | Prehnite | 9.DP.20 | Ca2Al2Si3O10(OH)2 |
| β | Laumontite | 9.GB.10 | CaAl2Si4O12 Β· 4H2O |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| H | β Laumontite | CaAl2Si4O12 · 4H2O |
| H | β Malachite | Cu2(CO3)(OH)2 |
| H | β Prehnite | Ca2Al2Si3O10(OH)2 |
| C | Carbon | |
| C | β Malachite | Cu2(CO3)(OH)2 |
| O | Oxygen | |
| O | β Andradite | Ca3Fe23+(SiO4)3 |
| O | β Cuprite | Cu2O |
| O | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| O | β Hematite | Fe2O3 |
| O | β Laumontite | CaAl2Si4O12 · 4H2O |
| O | β Malachite | Cu2(CO3)(OH)2 |
| O | β Prehnite | Ca2Al2Si3O10(OH)2 |
| O | β Quartz | SiO2 |
| O | β Hematite var. Specularite | Fe2O3 |
| O | β Andradite var. Topazolite | Ca3Fe23+(SiO4)3 |
| Al | Aluminium | |
| Al | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Al | β Laumontite | CaAl2Si4O12 · 4H2O |
| Al | β Prehnite | Ca2Al2Si3O10(OH)2 |
| Si | Silicon | |
| Si | β Andradite | Ca3Fe23+(SiO4)3 |
| Si | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Si | β Laumontite | CaAl2Si4O12 · 4H2O |
| Si | β Prehnite | Ca2Al2Si3O10(OH)2 |
| Si | β Quartz | SiO2 |
| Si | β Andradite var. Topazolite | Ca3Fe23+(SiO4)3 |
| S | Sulfur | |
| S | β Bornite | Cu5FeS4 |
| Ca | Calcium | |
| Ca | β Andradite | Ca3Fe23+(SiO4)3 |
| Ca | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Ca | β Laumontite | CaAl2Si4O12 · 4H2O |
| Ca | β Prehnite | Ca2Al2Si3O10(OH)2 |
| Ca | β Andradite var. Topazolite | Ca3Fe23+(SiO4)3 |
| Fe | Iron | |
| Fe | β Andradite | Ca3Fe23+(SiO4)3 |
| Fe | β Bornite | Cu5FeS4 |
| Fe | β Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| Fe | β Hematite | Fe2O3 |
| Fe | β Hematite var. Specularite | Fe2O3 |
| Fe | β Andradite var. Topazolite | Ca3Fe23+(SiO4)3 |
| Cu | Copper | |
| Cu | β Bornite | Cu5FeS4 |
| Cu | β Cuprite | Cu2O |
| Cu | β Malachite | Cu2(CO3)(OH)2 |
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Ganderia DomainDomain
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References
