Banks of Llano River: Crinoid Stem Rockhounding in Mason County, Texas

Updated June 2026

Banks of Llano River is a mapped rockhounding spot in Mason County, Texas. Reported finds include crinoid stem. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Mason County
State: Texas
Nearest road: Ranch Road 1871
Coordinates: 30.65979, -99.32436

Geology at Banks of Llano River

This spot sits on Gorman Formation, mapped as dolostone and limestone that formed roughly 485 to 470 million years ago. Carbonate rock like this dissolves and weathers readily, so fresh road cuts, quarries, and creek exposures are typically the most productive ground.

Mapped unit: Gorman Formation
Age: 485–470 Ma (Early Ordovician)
Rock types: dolostone and limestone
Elevation: 1,370 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 Banks of Llano River

Best months: September to May. Typical highs run 96°F in midsummer and 62°F in midwinter, with winter lows near 34°F. Summer heat here is intense, so carry more water than you think you need and work the early morning.

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

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.

State guidance last verified: April 1, 2026

Texas Parks and Wildlife Department
Bureau of Economic Geology, Texas geology
Big Bend National Park, Rules
Community submissions reviewed against published agency rules

Found at Banks of Llano River

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

Crinoid Stem Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Banks of Llano River.

Banks of Llano River FAQ

Where is Banks of Llano River?+

Banks of Llano River is in Mason County, Texas, at 30.65979, -99.32436. Nearest road: Ranch Road 1871.

What rocks and minerals can you find at Banks of Llano River?+

Banks of Llano River is reported to produce Crinoid Stem.

Is collecting allowed at Banks of Llano River?+

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 Banks of Llano River?+

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 Banks of Llano River?+

The most comfortable months at Banks of Llano River are September to May. Summer heat here is intense, so carry more water than you think you need and work the early morning.

How do I get to Banks of Llano River?+

Open the directions link to navigate to 30.65979, -99.32436 in Google Maps. The nearest road is Ranch Road 1871.

More rockhounding in Texas

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Open Banks of Llano River on the map

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