Tarryall Mountains (Spruce Grove): Smoky Quartz & Topaz Rockhounding in Park County, Colorado

Plan your visit

Generally open to casual rockhounding

County

Park County

State

Colorado

Coordinates

39.13820, -105.46170

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: Use Spruce Grove Campground on County Road 77 about 13 miles north of Lake George as the public National Forest anchor; trails lead to nearby tailings. Collect on open forest ground rather than in the campground, and avoid the private Topaz Mountain fee-dig and any posted claims.

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 Tarryall Mountains (Spruce Grove)

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 78°F in midsummer and 39°F in midwinter, with winter lows near 8°F. At about 8,500 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, CHEESMAN station (11 mi away), adjusted for elevation.

Geology at Tarryall Mountains (Spruce Grove)

This spot sits on Rocks of Pikes Peak Batholith (1000-m.y. age group), mapped as granite and alkali feldspar granite that formed roughly 1600 to 1000 million years ago. Granitic ground like this typically carries quartz veins and pockets, and weathered crystals tend to collect in the soils and drainages below.

Mapped unit

Rocks of Pikes Peak Batholith (1000-m.y. age group)

Age

1600–1000 Ma (Mesoproterozoic)

Rock types

granite and alkali feldspar granite

Elevation

8,500 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