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

Updated July 2026

The Triassic diabase and basalt of the Culpeper Basin in Loudoun County host a classic Virginia zeolite suite, with prehnite, stilbite, natrolite, and datolite lining vugs and fractures. Mindat and Virginia geologic-survey records document the zeolite occurrences in the diabase, giving northern Virginia collectors a distinctive trap-rock mineral association. Reported finds include calcite, datolite, epidote, natrolite, stilbite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Loudon County photos

Public image records connected to this spot or its reported material.

1 photo

Representative specimen of botryoidal prehnite, a zeolite-suite mineral found in Loudoun County diabase

Quick details

Access: Public area
County: Loudoun County
State: Virginia
Nearest road: Cochran Mill Road
Postcode: 20176
Coordinates: 39.08189, -77.52190

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.

Best time to visit Loudon County

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).

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.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Loudon County

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

Nearby rockhounding spots

Other rockhounding spots within driving distance of Loudon County.

Across the state line from Loudon County

Loudon County is close enough to the Virginia border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Loudon County FAQ

Where is Loudon County?+

Loudon County is in Loudoun County, Virginia, at 39.08189, -77.52190. Nearest road: Cochran Mill Road.

What rocks and minerals can you find at Loudon County?+

Loudon County is reported to produce Calcite, Datolite, Epidote, Natrolite, Stilbite, Diopside, Magnetite, Prehnite, Quartz.

Is collecting allowed at Loudon County?+

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 Loudon County?+

A rock hammer, sturdy gloves, safety glasses, and a collecting bag cover the basics here. Add a spray bottle: wet rock shows color and pattern that dry rock hides.

When is the best time to visit Loudon County?+

The most comfortable months at Loudon County are February to December.

How do I get to Loudon County?+

Open the directions link to navigate to 39.08189, -77.52190 in Google Maps. The nearest road is Cochran Mill Road.

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