Name Also Known As Variations Distribution Complete Description  Complete Pictures Added Sacramento Mountains Wood           Saddle Mountains Basalt           Saddle Mountains Wood           Sage Creek Wood           Sagebrush Jasper           Saginite           Saglek Chert           Salaberry-De-Valleyfield Chalcedony           Salem Chert           Salem Quartzite           Sallisaw Chert           Salmon Creek Chert Salmon Peak Chert         Salt & Pepper Quartzite           Saltville Chert           San Andres Chert Fingerprint Chert         San Angelo Chert           San Antonio Mountain Dactite           San Felipe Obsidian           San Francisco Mountains Obsidian Type B (Agassiz Saddle)           San Francisco Mountains Obsidian Type A (Fremont)           San Gabriel Chert           San Rafael Jasper           San Tank Obsidian           Sanders Chert           Sandsuck Argillite           Sangre de Cristos Chert           Santa Cruz Island Chert           Santa Elena Chert           Santa Rita Turquoise           Santee Chert           Saratoga Valley Wood           Sasema Jasper Kiwi Jasper         Saugeen River Gravel Chert           Saugus Jasper           Saugus Rhyolite           Savannah River Agate           Sawatch Quartzite           Scenk Chalcedony           Schistose Quartzite           Schmitt Chert           Schoharie Chert Aquetuck Chert         Schoharie Wood           Schroyer Chert           Schwartz Canyon Wood           Scioto Chert           Scoria           Scotch Grove Chert           Scotia Oolite Chert           Scots Bay (mustard) Jasper           Scott Canyon Radiolarian Chert           Sedalia Chert           Seldovia Wood           Selkirk Chert Dundee Chert         Selwyn Chert           Seneca Sandstone           Sentinel Butte Nadular Chert Miocene Chert         Sentinel Butte Porcellanite           Sentinel Butte Tabular Chert Miocene Chert         Sepulvida Chert           Sequoia Wood Sequoyah Wood, Sequoya Root Wood, Sequoia Root Wood         Sequoya Wood Sequoia Root         Serpentine           Sespe Sandstone           Setters Quartzite           Setters Quartzite           Seventy Six Basalt           Severn River Gravel Chert           Sewickley Chert           Sexton's Creek Chert           Sexton's Creek Quartzite           Shady Chert           Shadygrove Chert           Shakopee Chert / Dolomite           Shakopee Oolitic Chert           Shale           Shawangunk Conglomerate           Shawnee Chert           Shear Zone Chalcedony           Sheep Creek Quartzite           Sheguiandah Quartzite           Sheldon Chert           Shell Rock Chert           Shelldon Chert           Shemya Island Argillite           Shenandoah Valley Chert           Shequindah Quartzite           Shinarump Agatized Wood           Shippensburg Jasper           Shirley Basin Wood           Shiver Chert Old Port Chert         Shoshone Falls Rhyolite           Siding Hill Chert           Siemens Creek Basalt           Sierra Jasper Hornitas Jasper         Signal Mountain Jasper           Signal Wood           Silicified Siltstone           Silicified Coral           Silicified Dinosaur Bone           Silicified Fossilferous Sandstone           Silicified Sandstone Sedimentary Quartzite         Silicified Sandstone / Siltstone / Mudstone           Silicified Siltstone Chert Pebbles           Silurian Chert           Silver Hill Quartzite           Silver Mound Silicified Quartzite           Similkameen Valley Chert           Sinter           Sioux Falls Jasper           Sioux Quartzite           Sitgreaves Mountain Obsidian           Sixteen 0 Four (1604) Chert           Skaggs Blue Jasper           Skiatook Agatized Wood           Skidmore Island Chert           Skolai Pass Obsidian           Skukum Rhyolite           Skunnemunk Puddingstone           Sky Hill Chert Mahoning Chert, Lawrence County Chert         Slate           Slate Jack Canyon Slate           Slate Mountain Obsidian Wallace Tank Obsidian         Slater Agate / Chalcedony           Slaven Chert Slaven Radiolarian Chert, Srathearn Radiolarian Chert         Sleeping Beauty Turquoise           Smith Black Matrix Turquoise           Smith Creek Wood           Smokey Hill Jasper           Smokey Hill Quartzite           Smokey Hill Silicified Chalk           Smokey Hills Chert           Smokey Hills Jasper Niobrara         Smokey Hills Quartzite           Smokey Valley Turquoise           Smoky Hills Jasper Niobrara         Snake Hill Chert           Snake River Gravel Chert           Snake Valley Jasper           Snakeskin Coral           Snowville Turquoise           Snyder Creek Chert           Soapstone           Soda Butte Wood           Solidified Volcanic Ash           Somerset Chert           Somerville Chert           Sonoma Creek Wood           Sonora Flint Kentucky Blue Chert         Sopris Jasper           South Bend Chert           South Hills Jasper           South Mountain Chert           South Park Wood (Type 1)           South Park Wood (Type 12)           South Park Wood (Type 5)           Spanish Diggings Agate           Spanish Diggings Chert           Spanish Diggings Dendritic Jasper           Spanish Diggings Quartzite           Spanish Diggings Red Breccia           Spanish Point Dendritic Agate           Spavinaw Chert Eucha Chert         Specimen Creek Wood           Specimen Ridge Wood           Spencer Opal           Spergen Chert           Spergen Crystalline Saccaroidal Dolomite         Sperry Agatized Wood           Sphalerite           Spherulitic Rhyolite           Spiculitic Chert           Spider Web Jasper Peratite         Spoon Chert           Spor Mountain Jasper           Spotted Ridge Argillite           Spotted Ridge Chert           Spring Branch Chert           Spring Branch Chert           Spring Branch Rhyolite           Spring Canyon Jasper           Spring Canyon Quartzite           Spring Hill Chert           Springtime Jasper           Squaw Creek Opal           St. Agatha Limestone           St. Albans Chert Champlain Valley Chert, Hathaway Chert         St. Andrews Quartzite           St. David Chert           St. Francois  Rhyolite           St. Joe Chert           St. Joe Chert           St. John's Agate           St. Johns Jasper           St. Joseph Island Puddingstone           St. Louis Chalcedony           St. Louis Green Chert St. Louis Formation Chert         Staghorn Coral           Stanford Chert           Stanley Chert           Stanley Shale           Starburst Coral           Starved Rock Chert           Ste. Genevieve Chert Kentucky Hornstone         Steel Creek Chert           Steens Mountain Basalt           Stefoinite Brecciated Jasper           Stennich Turquoise           Stiger Wood (Type 1)           Stiger Wood (Type 2)           Stilbite           Stinking Water Jasper           Stinking Water Wood           Stirling Quartzite           Stockton Mudstone           Stone Canyon Jasper           Stone City Chert           Stone Mountain Turquoise           Stonehenge Chert           Stoner Chert           Stonewall Pass Agatized Wood           Stoney Creek (Brecciated) Jasper           Stoney Creek Chert           Stoney Creek Gneiss           Stoney Ridge Chert           Stonyford Jasper           Stooping River Gravel Chert           Storey County Sinter           Stormy Mountain Turquoise           Strawberry Chert           Stringtown Chert           Stuart Fork Argillite           Stuart Fork Chert           Succor Creek Jasper           Sudbury Melonite           Suemez Island Obsidian Cape Felix Obsidian and Group Z Obsidian         Sugar Creek Chert           Sugarloaf Mountain Quartzite           Summerville Chert           Sump Agatized Wood           Sunset Agate           Sunset Jasper           Susses County Petrified Wood           Suwannee River Agatized Coral           Suwannee River Chert Aucilla Chert         Swan Creek jasper           Swan Creek Quartzite           Swan Peak Quartzite           Swan River Chert           Swan River Chert           Swannee River Agatized Coral           Swartz Canyon Wood           Swauger Quartzite           Sweet Home Wood           Sweetwater Coral           Sweetwater Moss Agate           Syenite