Siskiwit Lake (South Side): Chlorastrolite Rockhounding in Keweenaw County, Michigan

Updated June 2026

Siskiwit Lake (South Side) is a mapped rockhounding spot in Keweenaw County, Michigan. Reported finds include chlorastrolite. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Permission required
County: Keweenaw County
State: Michigan
Nearest road: Ishpeming Trail
Coordinates: 47.98871, -88.80738

Geology at Siskiwit Lake (South Side)

This spot sits on Portage Lake Volcanics, mapped as basalt that formed roughly 1200 to 1000 million years ago. Volcanic ground like this weathers into rocky slopes and float, and fresh exposures in cuts and drainages are usually the most productive places to look.

Mapped unit: Portage Lake Volcanics
Age: 1200–1000 Ma (Mesoproterozoic)
Rock types: basalt
Elevation: 660 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 Siskiwit Lake (South Side)

Best months: April to October. Typical highs run 74°F in midsummer and 21°F in midwinter, with winter lows near 1°F.

Climate normals: NOAA 1991-2020 monthlies, GRAND PORTAGE station (41 mi away).

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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: April 1, 2026

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

Found at Siskiwit Lake (South Side)

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

Chlorastrolite

Nearby rockhounding spots

Other rockhounding spots within driving distance of Siskiwit Lake (South Side).

Across the state line from Siskiwit Lake (South Side)

Siskiwit Lake (South Side) 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.

Siskiwit Lake (South Side) FAQ

Where is Siskiwit Lake (South Side)?+

Siskiwit Lake (South Side) is in Keweenaw County, Michigan, at 47.98871, -88.80738. Nearest road: Ishpeming Trail.

What rocks and minerals can you find at Siskiwit Lake (South Side)?+

Siskiwit Lake (South Side) is reported to produce Chlorastrolite.

Is collecting allowed at Siskiwit Lake (South Side)?+

Permission required before collecting. Requires landowner or agency permission before any collecting. Do not enter without explicit authorization. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Siskiwit Lake (South Side)?+

A rock hammer, sturdy gloves, safety glasses, and a collecting bag cover the basics here. Add a spray bottle: wet rock shows color and pattern that dry rock hides.

When is the best time to visit Siskiwit Lake (South Side)?+

The most comfortable months at Siskiwit Lake (South Side) are April to October.

How do I get to Siskiwit Lake (South Side)?+

Open the directions link to navigate to 47.98871, -88.80738 in Google Maps. The nearest road is Ishpeming Trail.

More rockhounding in Michigan

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Open Siskiwit Lake (South Side) on the map

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