Michigamme Mine: Chalcedony & Hematite Rockhounding in Marquette County, Michigan

Plan your visit

Generally open to casual rockhounding

County

Marquette County

State

Michigan

Nearest road

US 41;M 28

Postcode

49861

Coordinates

46.53861, -88.09722

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

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.

Best time to visit Michigamme Mine

Comfortable months (45 to 90°F highs)

Best months: April to October. Typical highs run 77°F in midsummer and 23°F in midwinter, with winter lows near 2°F.

Climate normals: NOAA 1991-2020 monthlies, CHAMPION VAN RIPER PK station (5 mi away).

Geology at Michigamme Mine

This spot sits on Baraga Group; Michigamme Formation; Gray to black slate, mapped as slate that formed roughly 2500 to 1600 million years ago. Metamorphic rock like this weathers into resistant float, and minerals that survive transport typically concentrate in nearby drainages.

Mapped unit

Baraga Group; Michigamme Formation; Gray to black slate

Age

2500–1600 Ma (Paleoproterozoic)

Rock types

slate

Elevation

1,590 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.

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: April 1, 2026

• Michigan DNR, Rockhounding rules
• Michigan Geological Survey
• Isle Royale National Park, Rules
• Community submissions reviewed against published agency rules