Brown’s Gulch: Sapphire Rockhounding in Silver Bow County, Montana

Updated June 2026

Brown’s Gulch is a mapped rockhounding spot in Silver Bow County, Montana. Reported finds include sapphire. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Silver Bow County
State: Montana
Postcode: 59748
Coordinates: 46.01445, -112.68482

Geology at Brown’s Gulch

This spot sits on Surficial deposits, mapped as sand and gravel that formed within roughly the last 3 million years. Loose deposits like these are float-collecting ground: erosion keeps moving durable rocks and minerals into gravel bars, cutbanks, and washes.

Mapped unit: Surficial deposits
Age: 3 Ma to present (Pleistocene to Holocene)
Rock types: sand and gravel
Elevation: 5,310 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 Brown’s Gulch

Best months: April to October. Typical highs run 82°F in midsummer and 33°F in midwinter, with winter lows near 9°F.

Climate normals: NOAA 1991-2020 monthlies, BUTTE BERT MOONEY AP station (9 mi away), adjusted for elevation.

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.

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

BLM Montana — Recreational mineral collecting
Montana Bureau of Mines and Geology
Gem Mountain Sapphire Mine (fee-dig operator)
Community submissions reviewed against published agency rules

Found at Brown’s Gulch

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

Sapphire Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Brown’s Gulch.

Brown’s Gulch FAQ

Where is Brown’s Gulch?+

Brown’s Gulch is in Silver Bow County, Montana, at 46.01445, -112.68482.

What rocks and minerals can you find at Brown’s Gulch?+

Brown’s Gulch is reported to produce Sapphire.

Is collecting allowed at Brown’s Gulch?+

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 Brown’s Gulch?+

A rock hammer, a sieve, and a small shovel work well for garnet-type minerals, which concentrate as resistant grains in soils and creek gravels.

When is the best time to visit Brown’s Gulch?+

The most comfortable months at Brown’s Gulch are April to October.

How do I get to Brown’s Gulch?+

Open the directions link to navigate to 46.01445, -112.68482 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Montana

See all 87 Montana spots →

Open Brown’s Gulch on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.