Calcite has been recorded at 123 places in 30 states on the USA Rockhounding map. Illinois, Indiana and Missouri have the most. 2 are marked Ready, 10 Conditional and 107 research only, so check each place’s status before you go.
Calcite sites by state
Places to find calcite
The 60 places below are sorted with Ready sites first. Open the map to see all 123.
- Sheffler Rock Shop & Geode Mine, Clark County, Missouri: Ready
- Sterling Hill Mining Museum — Mine Run Dump, Sussex County, New Jersey: Ready
- Keokuk Geode Family Fest 2026 — Guided Geode Hunts, Lee County, Iowa: Conditional
- Keokuk-Area Private Geode Collecting — Permission Required, Lee / Henry / Van Buren County, Iowa: Conditional
- Warsaw Formation Streams & Ravines — Geode Context, Lee / Henry / Van Buren County, Iowa: Conditional
- Iowa Private Quarry / Gravel Pit Collecting Context, Statewide County, Iowa: Conditional
- Kansas Private-Land Fossil & Mineral Collecting — Permission Required, Statewide County, Kansas: Conditional
- Michigan Private Mine / Quarry / Mineral Club Field Trips, Statewide County, Michigan: Conditional
- Minnesota Private Quarry / Gravel Pit / Club Field Trips, Statewide County, Minnesota: Conditional
- North Dakota Private Quarry / Gravel Pit / Landowner Field Trips, Statewide County, North Dakota: Conditional
- South Dakota Private Mine / Quarry / Claim Field Trips, Statewide County, South Dakota: Conditional
- Wisconsin Private Quarry / Mineral Club Field Trips, Statewide County, Wisconsin: Conditional
- Alabama Limestone & Dolomite Resource Research, North / central Alabama County, Alabama: Research only
- Northern Arkansas Mississippi Valley-Type District, Boone / Marion / Baxter / Sharp / Lawrence County, Arkansas: Research only
- North Canaan Marble & Lime Research, Litchfield County, Connecticut: Research only
- Cockeysville Marble Research in Delaware, New Castle County, Delaware: Research only
- Delaware Piedmont Marble Research, New Castle County, Delaware: Research only
- Fort Drum / Rucks Pit Calcite Research Context, Okeechobee County, Florida: Research only
- Adams Rockhounding & Geology Research Index, Adams County, Illinois: Research only
- Brown Rockhounding & Geology Research Index, Brown County, Illinois: Research only
- Gallatin Rockhounding & Geology Research Index, Gallatin County, Illinois: Research only
- Hamilton / Hancock County Geode Context, Hancock County, Illinois: Research only
- Hancock Rockhounding & Geology Research Index, Hancock County, Illinois: Research only
- Cave-in-Rock Fluorite District, Hardin County, Illinois: Research only
- Hardin Rockhounding & Geology Research Index, Hardin County, Illinois: Research only
- Rosiclare Fluorspar District, Hardin County, Illinois: Research only
- Illinois-Kentucky Fluorspar District, Hardin / Pope / Gallatin County, Illinois: Research only
- Southern Illinois Barite–Galena–Calcite Research, Hardin / Pope / Gallatin / Saline County, Illinois: Research only
- Henderson Rockhounding & Geology Research Index, Henderson County, Illinois: Research only
- Galena / Upper Mississippi Valley Lead-Zinc District, Jo Daviess County, Illinois: Research only
- Mercer Rockhounding & Geology Research Index, Mercer County, Illinois: Research only
- Pope Rockhounding & Geology Research Index, Pope County, Illinois: Research only
- Saline Rockhounding & Geology Research Index, Saline County, Illinois: Research only
- Schuyler Rockhounding & Geology Research Index, Schuyler County, Illinois: Research only
- Illinois Dolostone State Rock Research, Statewide County, Illinois: Research only
- Illinois Geode Research Index, Western Illinois County, Illinois: Research only
- Geneva Dolomite Calcite & Fossil Context, Bartholomew / Decatur / Jennings County, Indiana: Research only
- Brown Rockhounding & Geology Research Index, Brown County, Indiana: Research only
- Southern Indiana Stream Geode Concentration Context, Brown / Monroe / Morgan / Owen / Lawrence / Washington / Harrison County, Indiana: Research only
- South-Central Indiana Geode Belt, Brown / Monroe / Morgan / Owen / Putnam / Lawrence / Washington / Harrison County, Indiana: Research only
- Crawford Rockhounding & Geology Research Index, Crawford County, Indiana: Research only
- Harrison Rockhounding & Geology Research Index, Harrison County, Indiana: Research only
- Lawrence Rockhounding & Geology Research Index, Lawrence County, Indiana: Research only
- Bedford–Bloomington Oolitic Limestone District, Lawrence / Monroe County, Indiana: Research only
- Monroe Rockhounding & Geology Research Index, Monroe County, Indiana: Research only
- Harrodsburg Limestone Geode Research, Monroe / Lawrence / Owen County, Indiana: Research only
- Indiana Limestone / Salem Limestone Belt, Monroe / Lawrence / Owen County, Indiana: Research only
- Indiana Mississippian Chert & Limestone Context, Monroe / Lawrence / Owen / Orange / Washington / Crawford / Harrison County, Indiana: Research only
- Ramp Creek Formation Geode Research, Monroe / Lawrence / Owen / Putnam / Harrison County, Indiana: Research only
- Morgan Rockhounding & Geology Research Index, Morgan County, Indiana: Research only
- Orange Rockhounding & Geology Research Index, Orange County, Indiana: Research only
- Owen Rockhounding & Geology Research Index, Owen County, Indiana: Research only
- Putnam Rockhounding & Geology Research Index, Putnam County, Indiana: Research only
- Washington Rockhounding & Geology Research Index, Washington County, Indiana: Research only
- Dubuque Lead-Zinc District Research, Dubuque County, Iowa: Research only
- Keokuk Geode Region Research, Lee / Henry / Van Buren County, Iowa: Research only
- Warsaw Formation Geode-Bearing Strata Research, Lee / Henry / Van Buren County, Iowa: Research only
- Southeast Kansas Lead-Zinc District Research, Cherokee County, Kansas: Research only
- Eastern Kansas Permian Limestone Research, Eastern / Central Kansas County, Kansas: Research only
- Kansas Calcite & Geode Occurrence Research, Statewide County, Kansas: Research only
What calcite is
Calcite is calcium carbonate, the main mineral in limestone and marble and one of the most common crystals in caves, geodes and veins. It forms many crystal shapes, from sharp “dogtooth” scalenohedrons to flat rhombs, and clear Iceland spar shows double refraction: text seen through it appears doubled. Many calcite specimens glow under ultraviolet light.
How to identify calcite
- Soft: a knife or steel nail scratches it easily (hardness 3).
- Breaks into rhomb-shaped pieces along three flat cleavage planes.
- Fizzes in dilute acid and slowly in vinegar.
- Clear pieces show double images of lines seen through them.
Where calcite is found
Calcite is widespread wherever limestone occurs, especially in the Midwest: geodes from the Keokuk region, the Illinois–Kentucky fluorspar district, the Missouri and Tennessee lead-zinc districts, and quarries across the Ohio Valley. It also lines cavities in volcanic rock in the West.
Rules
Most calcite localities are quarries and private land: ask permission and follow quarry safety rules. Caves are protected, and removing cave formations is illegal on federal land and in most states.
Questions
How can I tell calcite from quartz?
Calcite is soft enough to scratch with a knife, breaks into flat rhombs and fizzes in acid or vinegar. Quartz scratches glass and does not fizz.
Does calcite glow under UV light?
Many calcite specimens fluoresce, often red, orange or pink, under shortwave or longwave ultraviolet light.
What the map statuses mean is explained in how map statuses work; collecting rules for each kind of land are in rules by land type.
Other rocks and minerals
Agate · Geodes · Quartz · Jasper · Petrified Wood · Fossils · Shark Teeth · Gold · Garnet · Sapphire · Crystals · Chalcedony · Copper · Diamonds · Fluorite · Mica · Pyrite · Beryl, Aquamarine & Emerald · Tourmaline
Data: USA Rockhounding atlas records, checked through 2026-08-30. See all rocks and minerals.