Hoffman Mine, Sunset Lake, Bridgewater Township, Somerset County, New Jersey, USAi
| Regional Level Types | |
|---|---|
| Hoffman Mine | Mine |
| Sunset Lake | Lake |
| Bridgewater Township | Township |
| Somerset County | County |
| New Jersey | State |
| USA | Country |
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Latitude & Longitude (WGS84):
40° 38' 32'' North , 74° 37' 46'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Bedminster | 8,165 (2017) | 4.4km |
| Far Hills | 930 (2017) | 4.7km |
| Bridgewater | 44,464 (2017) | 4.9km |
| Green Knoll | 6,200 (2017) | 4.9km |
| Borough of Far Hills | 919 (2011) | 5.4km |
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 |
|---|---|---|
| Morris Museum Mineralogical Society | Morristown, New Jersey | 21km |
| New Jersey Mineralogical Society, Inc | Mountainside, New Jersey | 23km |
| North Jersey Mineralogical Society, Inc. | Paterson, New Jersey | 49km |
Mindat Locality ID:
12606
Long-form identifier:
mindat:1:2:12606:4
GUID (UUID V4):
3367d984-29df-4235-9779-c243bc457682
A copper mine in sandstone and brecciated trap rock (Watchung basalt). Ore body was 4 feet (1.3 meters) thick. Located 2 miles NW of the Somerset Mine and ¾ mile SE of Pluckemin in an area now known as Sunset Lake, Bridgewater Twp.
Woodward (1944) states: “The locality was prospected early in the 19th century and a mine was mentioned at this place in a report dated 1812. The main shaft, which penetrates shale, sandstone and basalt, is said to be 136 feet deep. The ore was reported to be four feet thick and to contain some native copper. The old mine dump when examined in 1905, showed chalcocite in sandstone and brecciated basalt, with smaller quantities of chrysocolla and malachite. The broken basalt may indicate a local zone of faulting. This mine was operated by the True Vein Copper Company of Philadelphia, yielding several tons of ore that was sent to Bergen Point. The main period of its activity was during the Civil War and three subsequent years. It has not been worked since 1868.”
Woodward (1944) gives the position of the Hoffman Mine as “the west flank of the First Watchung ...” while the accompanying map indicates it to be on the east flank. This may be because throughout most of the Watchung syncline the top of the Orange Mountain (First Watchung) basalt and the overlying Feltville formation is on the west flank of the ridge. However, at the northern and southern ends of this structure this is not the case. This is a classic example of the discrepancies in the literature that make locating old mines difficult. From Woodward's description of the prospect, his map and other documents it seems as though the map is correct.
The Hoffman prospect is just south of where the surface outcrop of the OMB ends, cut off by faulting. This is also just south of the present location of I-78. It is one of several copper occurrences in the Washington Valley, above the OMB. For more information on these occurrences see the copy for the Feltville copper mine.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Chalcocite Formula: Cu2S References: |
| ⓘ Chrysocolla Formula: Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| ⓘ Copper Formula: Cu References: |
| ⓘ Malachite Formula: Cu2(CO3)(OH)2 References: |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Copper | 1.AA.05 | Cu |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Chalcocite | 2.BA.05 | Cu2S |
| Group 5 - Nitrates and Carbonates | |||
| ⓘ | Malachite | 5.BA.10 | Cu2(CO3)(OH)2 |
| Group 9 - Silicates | |||
| ⓘ | Chrysocolla | 9.ED.20 | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| H | ⓘ Malachite | Cu2(CO3)(OH)2 |
| C | Carbon | |
| C | ⓘ Malachite | Cu2(CO3)(OH)2 |
| O | Oxygen | |
| O | ⓘ Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| O | ⓘ Malachite | Cu2(CO3)(OH)2 |
| Al | Aluminium | |
| Al | ⓘ Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| Si | Silicon | |
| Si | ⓘ Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| S | Sulfur | |
| S | ⓘ Chalcocite | Cu2S |
| Cu | Copper | |
| Cu | ⓘ Chalcocite | Cu2S |
| Cu | ⓘ Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| Cu | ⓘ Copper | Cu |
| Cu | ⓘ Malachite | Cu2(CO3)(OH)2 |
Other Regions, Features and Areas containing this locality
North America PlateTectonic Plate
- Laurentides DomainDomain
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References
