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Cliff Mine: Copper & Calcite Rockhounding in Keweenaw County, Michigan

Updated August 2026

Cliff Mine is a mapped rockhounding spot in Keweenaw County, Michigan. Reported finds include copper, calcite, chlorite, epidote, laumontite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Map showing Cliff Mine in Keweenaw County, Michigan

Quick details

Access
Check locally

Geology at Cliff Mine

This spot sits on Portage Lake Volcanics, mapped as basalt that formed roughly 1200 to 1000 million years ago. Copper minerals such as malachite and chrysocolla typically show up where mineralized rock like this has weathered and oxidized near old workings.

Mapped unit
Portage Lake Volcanics
Age
1200–1000 Ma (Mesoproterozoic)
Rock types
basalt
Elevation
980 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Best time to visit Cliff Mine

Best months: April to October. Typical highs run 76°F in midsummer and 22°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, HANCOCK HOUGHTON CO AP station (16 mi away).

Land & collecting status

Confirm rules before collecting

Land status here is not confirmed. Verify with the managing agency before collecting — federal, state, and tribal rules differ.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

State guidance last verified:

Found at Cliff Mine

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Nearby rockhounding spots

Other rockhounding spots within driving distance of Cliff Mine.

Across the state line from Cliff Mine

Cliff Mine is close enough to the Michigan border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Cliff Mine FAQ

Where is Cliff Mine?+
Cliff Mine is in Keweenaw County, Michigan, at 47.37286, -88.31311.
What rocks and minerals can you find at Cliff Mine?+
Cliff Mine is reported to produce Copper, Calcite, Chlorite, Epidote, Laumontite, Prehnite, Isle Royale Greenstone.
Is collecting allowed at Cliff Mine?+
Confirm rules before collecting. Land status here is not confirmed. Verify with the managing agency before collecting — federal, state, and tribal rules differ. Always confirm current rules with the managing agency before a trip.
What tools should I bring to Cliff Mine?+
A rock hammer, gloves, and safety glasses are enough for oxidized copper ground. Look for green and blue staining on weathered rock and in old dump piles.
When is the best time to visit Cliff Mine?+
The most comfortable months at Cliff Mine are April to October.
How do I get to Cliff Mine?+
Open the directions link to navigate to 47.37286, -88.31311 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Michigan

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