About

Who we are

HOSTING GREAT FIELD TRIPS SINCE 1972! 2022 WAS OUR 50th ANNIVERSARY!

The Cooperative Field Trip Chairmen's Association ("CO-OP") was established in 1972. It currently has 10 Member Clubs located in Northern California. The CO-OP is a member of the California Federation of Mineralogical Societies (CFMS)

Each society hosts one or more field trips a year. Our annual seminar is in March with an educational speaker and a luncheon. We have a live auction with donated rocks, minerals and unrelated items. This is our main fund raiser.

The CO-OP elects officers annually. There are also Permanent Directors, Associate Directors, and Honorary Directors. 

The CO-OP has a Field Trip Coordinator, Historian, and Webmaster.

The CO-OP meets on a quarterly basis.

SPONSORING CLUBS

Calaveras Gem & Mineral Society

P.O. Box 517

Angels Camp, CA 95222

calaverasgemandmineralsociety@gmail.com

3rd Sunday, 12:00 noon (except July & August)

CGMS Club House

2500 Mecham Ranch Road

Angels Camp, CA 

Contra Costa Mineral and Gem Society

P.O. Box 842 Concord CA 94522

www.facebook.com/groups/CCMGS

2nd Monday, 6:30 p.m. Endeavor Hall, 

6008 Center Street 

Clayton CA 94517 

El Dorado County Mineral & Gem Society

P.O. Box 950

Placerville, CA 95667 

www.eldoradomineralandgem.org 

3rd Thursday, 7:00 p.m. 

American Legion Hall

4561 Greenstone Road

Placerville, CA 95667

Fossils For Fun Society

3600 Jackie Ct. Shingle Springs, CA 95682

www.facebook.com/fossilsforfunsociety

2nd Thursday, 7:00 p.m. (except July, Aug. & Dec.)

Woman’s Thursday Club Bldg.

10625 Fair Oaks Boulevard

Fair Oaks, CA 95628

Mother Lode Mineral Society

P.O. Box 1263

Modesto, CA 95353

www.motherlodemineralsociety.com

1st Sunday, 2:00 p.m. 

Tuolumne River Lodge

2429 River Rd., Modesto, CA 95351

Nevada County Gem & Mineral Society

P.O. Box 565 Nevada City, CA 95959

www.ncgms.org

1st Tuesday, 7:00 p.m.

Golden Empire Grange

11363 Grange Court

Grass Valley, CA 95945

Roseville Rock Rollers Gem & Mineral Society

P.O. Box 212

Roseville, CA 95678

www.rockrollers.com

2nd Tuesday, 7:00 p.m.

Garden Room, @The Grounds (Placer Co Fairgrounds)

800 All America City Boulevard

Roseville, CA 95678

Sacramento Mineral Society

Mailing Address: 5467 Ballantine Street #6

Sacramento, CA 95826

www.sacramentomineralsociety.org 

3rd Thursday, 7:00 p.m. 

4145 Branch Center Road 

Sacramento, CA 95827

Santa Clara Valley Gem and Mineral Society

P.O. Box 54

San Jose, CA 95103-0054

www.facebook.com/santaclaravalleygemandmineralsociety

4th Tuesday, 7:30 p.m.

100 Belwood Gateway (the Cabana Club)

Los Gatos, CA 95032

Stockton Lapidary & Mineral Club

3136 E. Anita Street

Stockton, CA 95205

www.stocktonlapidary.com

2nd Saturday 1:00 pm

3136 E. Anita Street

Stockton, CA 95205