Lost Creek: Amazonite Rockhounding in Deer Lodge County, Montana

Quick details

Access

Permission required

County

Deer Lodge County

State

Montana

Nearest road

Lost Creek Road

Coordinates

46.20873, -113.00319

Geology at Lost Creek

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

6,150 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 Lost Creek

Best months: March to October. Typical highs run 80°F in midsummer and 34°F in midwinter, with winter lows near 13°F.

Climate normals: NOAA 1991-2020 monthlies, ANACONDA station (5 mi away), adjusted for elevation.

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

• 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 Lost Creek

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

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