Rockhounding in Hillsborough County, FL: 54 USGS Mineral Sites (2026)

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

Past ProducerProducerProspectOccurrenceStatus unknown

49 paw pins; nearby sites are grouped into one pin. Hover or tap a pin for the site name. 1 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

Agglite Debris

We picked it because its USGS record mentions 2 gem or collectible minerals (Quartz, Fluorite) and 2 of our card minerals overall. That ties with 10 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 Phosphorus-Phosphates. Minerals mentioned: Quartz, Fluorite. Approx. location 27.915, -82.121. 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?

Unknown

Status not recorded.

Producer

Was producing when the record was made.

Plant

A processing plant site.

Prospect

Explored or test-dug, with no recorded production.

Past Producer

Produced ore or material at some point in the past.

Status terms come from USGS MRDS records.

Mineral cards

Quartz
Mohs 7. Six-sided points; smoky quartz is NH’s state gem. Mindat
12 sites
Fluorite
Mohs 4. Cubes in purple, green or yellow; many glow under UV. Mindat
11 sites

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

Minerals recorded here

Sand 7Collophane 3

Commodities

Sand 31Phosphorus-Phosphates 20Salt 1Vermiculite 1Iron 1

Sites (first 40)

Site	Commodity	Minerals recorded	Status	Approx. location
Lonesome Mine	Phosphorus-Phosphates	Collophane	Producer	27.749, -82.129
Big Four Mine	Phosphorus-Phosphates	Collophane	Producer	27.744, -82.078
Imc Agrico - Hopewell	Phosphorus-Phosphates	Collophane	Producer	27.934, -82.125
Dot Tampa - Benjamin Mine	Sand	Sand	Unknown	28.001, -82.542
Dot Tampa - Cason Mine	Sand	Sand	Unknown	28.038, -82.142
Dot Tampa - Pruitt Mine	Sand	Sand	Unknown	28.025, -82.292
Dot Tampa - Sydney Washer Mine	Sand	Sand	Unknown	27.943, -82.200
Dot Tampa - Tucker Jones Mine	Sand	Sand	Unknown	27.832, -82.335
Dot Tampa - Williams Mine	Sand	Sand	Unknown	28.009, -82.318
The Cone Corp. - Balm Road Mine	Sand	Sand	Unknown	27.770, -82.318
Farmland Hillsborough Reserve	Phosphorus-Phosphates	—	Unknown	27.739, -82.200
Hopewell Mine	Phosphorus-Phosphates	—	Producer	27.925, -82.105
S. E. Hillsborough	Phosphorus-Phosphates	—	Producer	27.690, -82.091
Tampa Cargil Inc.	Phosphorus-Phosphates	—	Plant	27.953, -82.438
Big Bend Terminal	Phosphorus-Phosphates	—	Plant	27.844, -82.388
Agglite Debris	Phosphorus-Phosphates	—	Past Producer	27.915, -82.121
Arco-Stanaland Ranch	Phosphorus-Phosphates	—	Producer	27.664, -82.091
Hillsborough Mines	Phosphorus-Phosphates	—	Past Producer	27.880, -82.121
Hunt Brothers Ranch	Phosphorus-Phosphates	—	Producer	27.675, -82.132
Boyette-Fishhawk	Phosphorus-Phosphates	—	Prospect	27.803, -82.223
Coronet Road Processing Plant	Phosphorus-Phosphates	—	Plant	27.115, -82.177
First Mississippi Chem. Tract	Phosphorus-Phosphates	—	Prospect	27.694, -82.189
Lithia-Boyette	Phosphorus-Phosphates	—	Prospect	27.842, -82.125
Tampa Salt & Service Company	Salt	—	Plant	27.928, -82.445
Port Sutton Plant & Mine	Phosphorus-Phosphates	—	Plant	27.903, -82.413
Verlite Co/ Tampa, Fla.	Vermiculite	—	Plant	27.986, -82.450
Plant City Cf	Phosphorus-Phosphates	—	Plant	28.019, -82.113
Florida Steel Corp/ Tampa Fla.	Iron	—	Producer	27.986, -82.450
Hillsborough Co.- Farmland/Brewster	Phosphorus-Phosphates	—	Prospect	27.800, -82.158
East Pierce Deposit	Phosphorus-Phosphates	—	Prospect	27.992, -82.167
Andrew Lynn Co. - Big Basin Commerce Pit	Sand	—	Producer	28.068, -82.636
Abray Constr. Co. - Lake Abray Pit	Sand	—	Producer	28.149, -82.608
Alvin Futch Co. - Grimmer Pit	Sand	—	Producer	28.063, -82.068
Azzarelli Development Corp. - Pruit Road Pit	Sand	—	Producer	28.025, -82.299
Kash & Karry Food Stores, Inc. - Harney Road Mine	Sand	—	Unknown	28.004, -82.388
James Hill Co. - Martinez Lake	Sand	—	Producer	27.821, -82.318
Phillips and Jordan - Rhodine Rode Pit	Sand	—	Producer	27.818, -82.273
Parkway Center Community - Parkway Pit	Sand	—	Producer	27.880, -82.367
Caloosa Shell Corp. - Concord Pit	Sand	—	Producer	27.699, -82.493
Hardaway Co. - Race Track Rd. Mine	Sand	—	Unknown	28.083, -82.623

Fossil collections

The Paleobiology Database lists 25 fossil collection records in Hillsborough County. These are research records, not public dig sites.

Nearby counties

Polk County · Pasco County · Manatee County · Hardee County · Hernando County

Florida mineral guides

Back to all Florida counties.

Is It Legal to Collect Rocks on Public Land? BLM, Forest Service and National Park Rules

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 October 2026

Rockhounding in Hillsborough County, Florida