Loudon County: Calcite & Datolite Rockhounding in Loudoun County, Virginia

Plan your visit

Generally open to casual rockhounding

County

Loudoun County

State

Virginia

Nearest road

Cochran Mill Road

Postcode

20176

Coordinates

39.08189, -77.52190

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: Zeolites occur in diabase and basalt exposures across Loudoun County. Active quarries require permission and are usually off-limits; collect from public road cuts and float, and never enter a working quarry without 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.

Best time to visit Loudon County

Comfortable months (45 to 90°F highs)

Best months: February to December. Typical highs run 87°F in midsummer and 42°F in midwinter, with winter lows near 25°F.

Climate normals: NOAA 1991-2020 monthlies, WFO STERLING station (8 mi away).

Geology at Loudon County

This spot sits on high-titanium quartz normative diabase, mapped as diabase that formed roughly 200 to 175 million years ago. Plutonic rock like this weathers slowly into grus and boulders, and the most productive collecting is typically in weathered zones and drainages.

Mapped unit

high-titanium quartz normative diabase

Age

200–175 Ma (Early Jurassic)

Rock types

diabase

Elevation

220 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.

• Virginia Energy, Geology and Mineral Resources
• Virginia State Parks
• George Washington & Jefferson National Forests
• Community submissions reviewed against published agency rules