Cheyenne Mineral and Gem Society

09/04/2026

USFS RockHounding Sites in Buffalo Grasslands of SD. Been to Weta and French Creek, and they have lots of rocks. Baja and Railroad Buttes? Anyone been there?

09/02/2026

Nebraska Blue Agates

Nebraska Blue is a blue chalcedony (pale to sky blue) that forms as nodules and seam fillings. Agates can have faint banding and are typically found in the Oglala National Grasslands, in both Dawes, and Sioux counties of Nebraska. It can be found as nodules within silt and claystone deposited in the Chadron Formation of Oligocene Age.

Blue chalcedony / agate was declared the official Nebraska state gemstone in 1967. Can you name the state rock, gemstone, or dinosaur of your home state?

Locations to look for NE Blue agates in western NE:

Dawes County: Breaks of the White River, Federal grazing lands in Crawford area, Lone Butte near Orella Railroad Station, Niobrara River, Chadron area washes and gravels to north of town

Sioux County: Gravel beds and cut banks of Hat Creek, Waldron Hills, gravels in the Montrose area

08/28/2026

Monthly Meetings to Start Up in September

CMGS
September 9, 2026
6:30 pm
IBEW Hall, Cheyenne
810 Fremont Avenue

08/26/2026

Field trip with Weld County Rock and Mineral Society was a huge hit. Everyone had a good time and lots of great samples of Labordorite from Plumbago Canyon going home. Thanks for hosting Weld County.

08/05/2026

Plume Agate Updates

Back in March 2025 the CMGS Facebook site gave a brief description of Medicine Bow Plume agates and a potential location for these unique agates at the intersection of Marshall and Holiday Road. This is an update after we visited Shirley Basin this spring looking for cool rocks.

Shirley Basin has a variety of rock types including petrified wood, chert, agates, jasper, and uranium. The back country has a number of roads and a good amount of public land to hunt rocks on. Remember these roads are generally remote without services (good tires, gas, water, etc are a must for the rock hounder). The rock hounding locations mentioned below may require a bit of digging and a small sledge or rock hammer. However, we did not work excessively hard. All of these sites are on BLM land. However, there is a fair amount of private land in the area, so have a good map to keep yourself located and out of trouble. Happy hunting.

Points of Interest Include:
1. As previously mentioned the Intersection of Marshall and Holiday Road (eroded Medicine Bow Plume agates. Look for smaller specimens associated with gravels and erosion (42° 17' 13.50" N 105° 54' 55.56" W)

2. Although not a rock there is an old abandoned drill rig (uranium?) sitting out on top of a hill. (42° 24' 38.42" N 106° 0' 46.98" W). Fun stop for the gear heads.

3. We found carmel colored jasper with pale blue chalcedony (42° 24' 45.71" N 106° 0' 51.89" W) at the end of an old road below the drill rig. This materail polishes and tumbles beautifully. (See picture below).

4. White and Black banded agates and Medicine Bow Plume agate with carmel colored matrix (pictures below) (42° 23' 55.87" N 106° 0' 42.47" W) along the west side of a small basin. At the base of the hill is smaller eroded agates, the outcrops near the top are in limestone. Look for zones (bedding parallel) of discoloration and alteration, and disturbed areas where others have dug around.

5. Town of Medicine Bow. The dinosaur bone house from Como Bluff was recently moved to town. Not sure if it is open for visitors yet. The Virginian across the street also offers cold b**r and dinner on the way home from a hard day of hunting rocks.

07/27/2026

Morning Rock Hounders

Tami Menk from Wellington has reached out to she is moving and has blue forest wood, petrified wood, amethyst crystals, and other rocks for sale to a new home. If you are interested she is about 30 minutes away from Cheyenne. Her number 507-469-0473. text or phone message works.

CMGS

07/24/2026

I think that there will
never be

An ignoramus just like me.

Who roams the hills
throughout the day
To pick up rocks
that do not pay.

For there’s one thing
I’ve been told:
I take the rocks and
leave the gold.

O’er deserts wild and
mountains blue
I search for rocks
of varied hue.

A hundred pounds or more
I pack

With blistered feet and
aching back,

And after this is said
and done.

I cannot name a single one.
I pick up rocks where
e’re I go,
The reason why
I do not know,

For rocks are found
by folks like me
Where God intended them
to be.

Collecting Rocks
By Hazel Hillmer

07/20/2026

Some favorites that we picked up this summer so far. Which one do you like best...

Fairburn Agate
Tuxedo Agate
Blue Lace Agate

More to follow as they finish up being polished...

07/14/2026

Summers here. Whats your favorite rock hounding finds for the year so far?

So far this year we have visited Shirley Basin and found a Medicine Bow plume agate, Crawford to look for Fairburns and jasper. We found one fairburn and lots of prairie agates and bubble gum agates. Got a suggestion for where to look for NE Blue, but weather turned hot and windy before we had a chance to look. Maybe next time.

Also managed to purchase some fine looking Tuxedo Lace , Blue Lace agates and WY Jade along the way.

and summer is only half over....

Send some pictures and a description of your favorite finds for the year.

Club also managed to do field trips to look for quartz geodes, petrified wood, jasper, and other great rocks.

CMGS

07/05/2026