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American Bar: Sapphire & Cassiterite Rockhounding in Lewis and Clark County, Montana

Public accessBest spot8 mineralsLewis and Clark County, MontanaUpdated June 2026
2 photos
Minerals reported
8
Elevation
3,680 ft
Best months
March to October

American Bar belongs to the upper Missouri River sapphire province, where GIA traces gem-quality sapphire mining back to 1865. The associated heavy-mineral suite, including cassiterite, garnet, kyanite, topaz, gold, and chalcedony, makes the Missouri River bars one of Montana's most mineralogically varied placer settings. Reported finds include sapphire, cassiterite, chalcedony, garnet, gold, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

State
Montana
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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.

Access note: Collect only on lawful public river-bar access and verify land status, mineral claims, and local restrictions before digging.

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 American Bar

Comfortable months (45 to 90°F highs)

Best months: March to October. Typical highs run 85°F in midsummer and 36°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, HOLTER DAM station (13 mi away), adjusted for elevation.

Geology at American Bar

This spot sits on Alluvial and colluvial deposits, mapped as sand and gravel that formed within roughly the last 3 million years. Stream-worked gravels like these are where placer gold tends to concentrate, settling toward bedrock, inside gravel bars, and behind boulders.

Mapped unit
Alluvial and colluvial deposits
Age
3 Ma to present (Quaternary)
Rock types
sand and gravel
Elevation
3,680 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.

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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 American Bar

Each name 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 American Bar.

American Bar FAQ

Where is American Bar?+
American Bar is in Lewis and Clark County, Montana, at 46.81306, -111.92923.
What rocks and minerals can you find at American Bar?+
American Bar is reported to produce Sapphire, Cassiterite, Chalcedony, Garnet, Gold, Kyanite, Limonite, Topaz.
Is collecting allowed at American Bar?+
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. Always confirm current rules with the managing agency before a trip.
What tools should I bring to American Bar?+
A gold pan, a classifier screen, a small shovel, and a snuffer bottle cover the basics. Motorized equipment and sluices fall under separate rules in most states, so start with hand tools.
When is the best time to visit American Bar?+
The most comfortable months at American Bar are March to October.
How do I get to American Bar?+
Open the directions link to navigate to 46.81306, -111.92923 in Google Maps. Some spots are remote, so check road conditions before driving out.

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