Centennial Cone: Aquamarine & Bertrandite Rockhounding in Jefferson County, Colorado

Plan your visit

Generally open to casual rockhounding

County

Jefferson County

State

Colorado

Nearest road

Elk Range Trail

Coordinates

39.75542, -105.36075

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.

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 Centennial Cone

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 79°F in midsummer and 37°F in midwinter, with winter lows near 15°F. At about 8,140 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, RALSTON RSVR station (8 mi away), adjusted for elevation.

Geology at Centennial Cone

This spot sits on ground mapped as Felsic gneiss that formed roughly 2500 to 1600 million years ago. Metamorphic terrain like this typically carries quartz veins and sweats, and weathered crystals tend to end up in the soils and streams below.

Mapped unit

Felsic gneiss

Age

2500–1600 Ma (Paleoproterozoic)

Elevation

8,140 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.

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.

• BLM Colorado rockhounding rules
• Colorado Geological Survey
• Pike and San Isabel National Forests
• Community submissions reviewed against published agency rules