Ohio is well-known for its minerals. At least 56 minerals species have been recorded from the state. Some examples are on exhibit in this display case.

Minerals in this Exhibit

Ohio Counties Represented

Minerals in this exhibit were collected from these Ohio counties: 

• Adams: Iron minerals 
• Allen: Fluorite 
• Coshocton: Diadochite 
• Erie: Calcite, whewellite 
• Franklin: Baryte, pyrite 
• Highland: Asphalt, bog (iron) ore 
• Huron: Quartz 
• Jefferson: Nellie blue flint 
• Lawrence: Hecla Furnace slag 
• Licking: Limonite, quartz 
• Logan: Pyrite 
• Lucas: Calcite, pyrite 
• Mahoning: Gypsum 
• Mercer: Sphalerite 
• Ottawa: Baryte, celestine, fluorite, galena, gypsum, sphalerite 
• Paulding: Calcite, fluorite 
• Ross: Pyrite 
• Sandusky: Galena, sphalerite, strontianite 
• Shelby: Marcasite 
• Van Wert: Calcite 
• Wood: Calcite, celestine, fluorite 

Specimen Details

• Asphalt: Asphalt in Cedarville Dolomite, Rucker Quarry, Hillsboro, Highland County, Ohio (OSU 13175). 
• Baryte:
  1. Baryte crystals in concretion, Columbus, Franklin County, Ohio (OSU 51871). 
  2. Baryte on dolostone, Clay Center, Ottawa County, Ohio (MIN 14564). 
• Calcite:
  1. Calcite with pink dolomite, Delphos, Van Wert County (donated by the late John Medici). 
  2. Calcite, Pugh Quarry, Weston, Wood County (donated by the late Dan Hall). 
  3. Calcite, var. dogtooth spar, Pugh Quarry, Weston, Wood County (OSU 22269). 
  4. Calcite, Kelleys Island, Erie County (donated by the late Dan Hall). 
  5. Calcite, Auglaize Quarry, Junction, Paulding County (donated by the late Dan Hall). 
  6. Scalenohedron with overgrowth, Maumee Stone Co. quarry, Toledo, Lucas County (donated by the late Dan Hall). 
• Celestine:
  1. Clay Center, Ottawa County (OSU 6191). 
  2. Lime City?, Wood County (OSU 26062). 
  3. Lime City, Wood County (donated by the late Dan Hall). 
  4. Stoneco Quarry, Portage, Wood County (OSU 51836).  
  5. Crystal Cave, Put-in-Bay, South Bass Island, Ottawa County (collected ca. 1897; donated by the late Dan Hall). 
  6. Lime City, Wood County (OSU 52606). 
  7. Celestine and calcite, White Rock quarry, Clay Center, Ottawa County (OSU 47312). 
  8. Celestine, Seaman Museum specimen. 
• Diadochite: Reclaimed coal mine, Jackson Township, Coshocton County (Min 12075). 
• Fluorite:
  1. Dolostone with vugs, Auglaize quarry, Junction, Paulding County (OSU 47508). 
  2. Fluorite with celestine (Seaman Museum specimens). 
  3. Dark brown fluorite (Seaman Museum specimen). 
  4. Fluorite with green iridescence, Clay Center, Ottawa County (Seaman Museum specimen 707). 
  5. Fluorite with golden iridescence, Clay Center, Ottawa County (Seaman Museum specimen 437). 
  6. Purple cubes of fluorite on blue iridescent fluorite, Auglaize quarry, Junction, Paulding County (OSU 51849). 
  7. Note on Jewelry: Fluorite is soft (4 on Mohs’ scale of hardness) with near-perfect octahedral cleavage, making it challenging to facet and unsuitable for standard jewelry. Featured crafted pieces include an orange gem from Lime City, Wood County (4.27 carats) and a clear stone from Bluffton, Allen County (14.4 carats). 
• Galena:
  1. Galena in limestone, Carmeuse Quarry, Millersville, Sandusky County (OSU 50486). 
  2. Galena crystals, Clay Center, Ottawa County (Seaman Museum specimen 1468). 
• Gold: Gold flakes, Scioto River, Lucasville, Ohio (OSU 52950). 
• Gypsum:
  1. Massive gypsum (Tymochtee Dolomite, Celotex Inc. quarry, Gypsum, Ottawa County; OSU 51870). 
  2. Selenite in matrix, Ellsworth, Mahoning County (OSU 18930; glacial clays here are world-famous for selenite crystals). 
  3. Selenite, Ellsworth, Mahoning County (OSU 49735).  
  4. Selenite, Webb Summit, Hocking County (OSU 53712). 
  5. Gypsum, var. satin spar, Ottawa County (donated by the late Dan Hall). 
• Iron Minerals:
  1. Limonite and hematite, Vanport Limestone (OSU 18936; source of the “ferriferous ore,” the chief ore of the Hanging Rock Iron Region). 
  2. Mammillary limonite, Licking County (OSU 48678; used as an ore by early Mary Ann and Granville Furnaces). 
  3. Bog ore, Sinking Springs, Highland County (OSU 5780; formed by precipitation in swamps/lowlands). 
  4. Slag from Hecla Furnace, Ironton, Lawrence County (OSU 1399; iron from here was used in the Civil War cannon The Swamp Angel). 
  5. Brassfield Limestone, Loudon, Adams County (OSU 51868; contains trilobites and cephalopods replaced by hematite). 
• Marcasite: Miami River Stone Co. quarry, south of Sidney, Shelby County (donated by the late Dan Hall). 
• Pyrite:
  1. Pyrite "snake", Ross County (OSU 43970). 
  2. Pyrite with dolomite, Duff Quarry, Huntsville, Logan County (OSU 47685). 
  3. Pyrite, diploid crystal form, Duff Quarry, Huntsville, Logan County (OSU 43766). 
  4. Pyrite nodule in shale, Glen Echo, Columbus, Franklin County (OSU-Min 7335). 
  5. Pyritized fossils (crinoids, cephalopods, brachiopods including Paraspirifer bownockeri), Silica Shale, Sylvania, Lucas County. 
• Quartz and Flint:
  1. Nellie blue flint, Jefferson Township, Jefferson County. 
  2. Quartz and ferroan dolomite, west branch of Huron River, Huron County (OSU 51846). 
  3. Worked flint, Flint Ridge, Licking County (OSU 7562, OSU-MIN 2229). 
  4. Quartz on flint, Toboso, Flint Ridge, Licking County (OSU 13695). 
• Sphalerite:
  1. Gibsonburg, Sandusky County (OSU-MIN 3568). 
  2. Karsch Stone Co. Quarry, Celina, Mercer County (OSU 42959). 
  3. Sphalerite w/ celestite & calcite, Clay Center, Ottawa County (Seaman Museum 1316). 
• Strontianite: Woodville, Sandusky County (OSU-MIN 12683). 

• Whewellite: Concretion in Huron River near Milan, Erie County (OSU 36054).

   

Ohio Minerals Not Featured in this Exhibit

• Anhydrite: Calcium sulfate mineral found only in the subsurface; changes to gypsum upon contact with water. 
• Apatite: Small crystals (less than 2 mm) known from concretions in the Huron Shale Member of the Ohio Shale near Milan, Ohio. 
• Aragonite: Calcium carbonate mineral known mostly from concretions. 
• Chalcopyrite: Rare copper-iron sulfide found in small amounts in ironstone concretions. 
• Coesite: High-pressure quartz form reportedly found at Serpent Mound impact structure. 
• Glauconite: Green mica occurring as thin films along bedding planes of marine rocks in western Ohio. 
• Hemimorphite: Zinc silicate found in fractures around the Serpent Mound impact structure. 
• Hydrozincite: Zinc carbonate occurring as a weathering product of sphalerite at Serpent Mound impact structure. 
• Pyrolusite: Manganese oxide occurring as dendritic coatings and bog ore with peat. 
• Siderite: Iron carbonate forming the main body of ironstone concretions. 
• Smithsonite: Zinc carbonate found in fractures at Serpent Mound impact structure. 
• Sulfur: Small bright yellow crystals occasionally found in vugs within carbonate rocks from the Findlay Arch area. 
• Vivianite: Phosphate mineral that turns deep blue upon air exposure; found in glacial sediments with fossil wood and bone. 
• Wurtzite: Zinc sulfide occurring as veins and radiating crystals in ironstone concretions in eastern Ohio black shales. 
• Efflorescent minerals: Minerals that form by evaporation of water, leaving crusty coatings. Examples include alunogen, botryogen, copiapite, epsomite, halotrichite, hexahydrite, melanterite (copperas), pickeringite, rozenite, szomolnokite, and thenardite. 

Acknowledgments

Some specimens in this exhibit were generously donated by the late Dan Hall and the late John Medici, and others were loaned by the A.E. Seaman Mineral Museum. This exhibit was produced with the assistance of the Mid-Ohio Mineral and Fossil Club of Mansfield, Ohio.