Where to Find Prehnite in Michigan
Michigan has 9 mapped collecting spots that report prehnite, spread across 2 counties. The largest share sits in Keweenaw County with 7 spots. 4 of the spots are on land mapped as publicly accessible.
Spot list checked against source data on April 1, 2026.
Every prehnite spot we track in Michigan
McClain State ParkHoughton County, MichiganPermission required · Adularia, Chalcedony, Chert +8- Calumet Waterworks ParkHoughton County, MichiganCheck locally · Lake Superior Agate, Prehnite, Natrolite +5
- Cliff NorthKeweenaw County, MichiganCheck locally · Copper, Calcite, Chlorite +5
Gratiot River County ParkKeweenaw County, MichiganPublic access · Freda Sandstone, Basalt, Rhyolite +5- Cliff MineKeweenaw County, MichiganCheck locally · Copper, Calcite, Chlorite +4
- High Rock BayKeweenaw County, MichiganPublic access · Prehnite, Calcite, Copper +4
- Esrey ParkKeweenaw County, MichiganPublic access · Granite, Prehnite, Copper +1
- Keweenaw Rocket RangeKeweenaw County, MichiganPublic access · Granite, Prehnite, Copper +1
- Seneca No. 1 ShaftKeweenaw County, MichiganPermission required · Copper, Datolite, Prehnite
Best counties for prehnite in Michigan
Ranked by the number of mapped prehnite spots. County links open the full rockhounding page for that county.
Before you go
Read the prehnite identification guide so you know what a keeper looks like in the field: Prehnite in the encyclopedia.
Prehnite in Michigan FAQ
Where can you find prehnite in Michigan?+
The mapped spots concentrate in Keweenaw County and Houghton County. Every spot on this page is on the map, and each spot's own page has its coordinates and access notes.
How many prehnite spots are mapped in Michigan?+
9 spots across 2 counties. The RockHoundR app keeps the same spots on an offline map with public land overlays, geology layers, and your saved finds.
Is it legal to collect prehnite in Michigan?+
Hand collecting of common rocks and minerals in small amounts for personal use is generally allowed on BLM and U.S. Forest Service land, with limits set by the local field office. National parks, most state parks, and tribal land are closed to collecting. 4 of the 9 mapped spots here sit on land marked public. Always confirm current rules with the managing agency before you dig.
Where else to find prehnite
More minerals to hunt in Michigan
Hunt prehnite in Michigan with the map in your pocket
RockHoundR puts these spots on an offline map with BLM and Forest Service overlays, geology layers, and a log for your finds.
