RockWoof
Check access before you go. Most sites listed here are old mines, quarries or prospects, and many are on private land or active mining claims. Get the landowner's permission, check the rules of the agency that manages any public land, and never enter mine workings. Locations are approximate.

Sketch map

Ladd Mine + 3 more nearby (Occurrence)Ladd Mine + 5 more nearby (Producer)Scott Prospect + 3 more nearby (Occurrence)Unnamed Location (Unknown)Callahan + 1 more nearby (Unknown)Cummings Mine (Producer)Unnamed Prospect (Occurrence)Lathrop Phos-Acid Plant (Unknown)Manteca Plant (Producer)Linden (Unknown)Clements (Producer)Mokelumne Pit (Unknown)Doodle Bug + 3 more nearby (Producer)Gold Hill Dredges (Unknown)Wallace Dredge + 1 more nearby (Unknown)Bellota (Producer)Gold Hill Dredges (Unknown)Unnamed Location (Unknown)Unnamed Gravel Pit (Unknown)Unnamed Location (Unknown)Unnamed Location (Unknown)
Past ProducerProducerProspectOccurrenceStatus unknown
21 paw pins; nearby sites are grouped into one pin. Hover or tap a pin for the site name. 2 site(s) with USGS coordinates outside the outline are not pinned. County outline: US Census Bureau cartographic boundary file (2023). Locations approximate.

Woof’s favorite find

Edna James

We picked it because its USGS record mentions 2 gem or collectible minerals (Gold, Silver) and 2 of our card minerals overall. That ties with 2 other site(s), so we broke the tie by mine status (past producers first), then USGS record quality, then name. USGS lists it as past producer for Gold. Minerals mentioned: Gold, Silver. Approx. location 38.230, -120.010. USGS record.

Ask first: a USGS record doesn’t mean you can visit. Find out who owns the land and get permission before collecting.

Field cards: what kind of sites?

17
Unknown

Status not recorded.

9
Producer

Was producing when the record was made.

5
Occurrence

The mineral was noted here, without development.

5
Past Producer

Produced ore or material at some point in the past.

3
Prospect

Explored or test-dug, with no recorded production.

Status terms come from USGS MRDS records.

Mineral cards

Counts are sites whose USGS record mentions the mineral or commodity. Hardness from Mindat.

Minerals recorded here

Bementite 3Psilomelane 1Hematite 1

Commodities

Gold 18Manganese 11Iron 1Calcium 1Phosphorus-Phosphates 1

Sites

SiteCommodityMinerals recordedStatusApprox. location
Cummings MineManganeseBementiteProducer37.584, -121.485
Ladd MineManganeseBementiteProducer37.607, -121.497
Fabian MineManganeseBementiteProducer37.611, -121.501
Ladd MineIronHematiteOccurrence37.615, -121.505
MahoneyManganesePsilomelaneProducer37.599, -121.498
Scott Prospect——Occurrence37.544, -121.524
ClementsGold—Producer38.233, -121.084
Ladd MineManganese—Producer37.600, -121.501
Cracker ProspectManganese—Occurrence37.541, -121.503
BellotaGold—Producer38.100, -121.001
Mahoney 1 Mine——Past Producer37.643, -121.500
Manteca PlantCalcium—Producer37.792, -121.201
Doodle BugGold—Producer38.171, -121.031
Scott Prospect——Prospect37.543, -121.525
Lathrop Phos-Acid PlantPhosphorus-Phosphates—Unknown37.807, -121.278
Murdoch RanchGold—Past Producer38.172, -121.031
Unnamed LocationGold—Unknown38.057, -120.931
Winship-DoakManganese—Unknown37.599, -121.504
Edna JamesGold—Past Producer38.230, -120.010
Unnamed Gravel PitGold—Unknown37.977, -120.987
Unnamed LocationGold—Unknown38.049, -120.959
Gold Hill DredgesGold—Unknown38.054, -120.991
Mokelumne PitGold—Unknown38.206, -121.062
Unnamed LocationGold—Unknown38.043, -120.977
Unnamed LocationGold—Unknown38.178, -121.041
Cummings MineManganese—Prospect37.631, -121.527
LindenGold—Unknown38.016, -121.096
San Joaquin 7 Mine——Prospect37.745, -121.656
Unnamed LocationGold—Unknown38.178, -121.040
Wallace DredgeGold—Unknown38.195, -120.983
CallahanManganese—Unknown37.603, -121.491
Unnamed LocationGold—Unknown37.666, -121.458
Unnamed LocationGold—Unknown38.188, -120.990
Unnamed ProspectManganese—Occurrence37.593, -121.455
Cummings——Past Producer37.586, -121.484
Crocker Prospect——Occurrence37.542, -121.506
Ladd Mine——Unknown37.607, -121.497
Fabian Mine——Past Producer37.631, -121.505
Gold Hill DredgesGold—Unknown38.214, -121.009

Fossil collections

The Paleobiology Database lists 12 fossil collection records in San Joaquin County. These are research records, not public dig sites.

Nearby counties

Alameda County · Stanislaus County · Contra Costa County · Santa Clara County · Solano County

California mineral guides

Back to all California counties.

Related articles

How we built this page: we counted named sites in the USGS Mineral Resources Data System (MRDS) for this area, left out sand, gravel, crushed stone, clay pits and unnamed sites, grouped them by Census county, and linked every site to its USGS record. We did not visit these sites, and MRDS does not tell you who owns the land or whether collecting is allowed.

Source: USGS Mineral Resources Data System (MRDS). USGS ceased systematic updates to MRDS around 2011, so status and details may be out of date. Each site links to its USGS record.

Updated