Fisherman's Island State Park: Petoskey Stone & Charlevoix Stone Rockhounding in Charlevoix County, Michigan

Plan your visit

Pay-to-dig site

County

Charlevoix County

State

Michigan

Postcode

49720

Coordinates

45.30801, -85.31020

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

Land & collecting status

Pay-to-dig site

This is a fee-dig location. Hours, prices, and what you can keep vary by operator. Call ahead before driving out.

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 Fisherman's Island State Park

Comfortable months (45 to 90°F highs)

Best months: April to November. Typical highs run 76°F in midsummer and 29°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, CHARLEVOIX station (2 mi away).

Geology at Fisherman's Island State Park

This spot sits on Traverse Group, mapped as limestone that formed roughly 395 to 385 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Mapped unit

Traverse Group

Age

395–385 Ma (Middle Devonian)

Rock types

limestone

Elevation

610 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