Name Also Known As Variations Distribution Complete Description  Complete Pictures Added Aarde Shale     x     Aaron Slate     x     Abbyville Gabbro     x     Abiathar Peak Petrified Wood     X X X Abingdon Chert Holston Chert         Abique Agate     X   X Abiquiu Jasper     X     Abiquiu Moss Agate     X     Abiquiu Quartz     X     Abiquiu Quartzite     X   X Abitibi Chert Lake Abitibi Chert         Abo Sandstone     x     Absaroka Chert           Accomack Mudstone     X X   Actinolite           Ada Petrified Wood     X     Addy Quartzite     X     Adin Chalcedony           Adna Carnelian           Adobe Flat Mudstone           Afton Canyon Jasper           Agagonite           Agate Breccia           Agate Jasper           Agate Springs (dendritic) Chert           Agatized Coral (Florida)           Agatized Coral (Michigan)           Agatized Glacial Till Wood Silicified Glacial Till Wood         Agatized Palm Root (California)           Agatized Palm Root (Nebraska)           Agatized Palm Root (Texas)           Agatized Wood           Agattu Island Argillite           Agort Chert           Agort Quartzite           Agua Dulce Vasquez Rocks         Ahorn Quartzite           Ajax Turquoise           Ajibik Quartzite           Akmalik Chert EMF Chert and Black Lisburne         Alabaster (California)           Alabaster (Texas)           Alachua Chert           Alaska Diamond (Hemetite) Alaska Black Diamond         Alaska Peninsula Wood           Alaskan Jade           Albanel Quartzite Mistassini Quartzite         Alberene Soapstone           Alder Creek Jasper           Alderson's Pine Wood           Aleman Ribbon Chert           Algal Mound Chert           Algic Chert           Alibates Agatized Dolomite           Alibates Chert (Silicified Dolomite)           Allamoore Ribbon Chert           Allen Creek Chert           Allenby Chert           Allendale Chert Costal Chert         Allentown Chert Upper Allentown Chert         Alligator Back Gneiss           Alma Quartzite Buffalo County Quartzite and Lacross County Quartzite         Alpine Agate           Alsen Chert Helderberg Chert         Alum Creek Chert           Alvord Mountains Jasper           Alvord Mountains Opalized Wood           Amabel Formation Chert           Amana Sandstone           Amazon Jade Colorado Jade         Amazonite Amazon Stone         Amber           Amber Chalcedony           Amboy           Amethyst           Amethyst Mountain Wood           Amherst Red Stone           Amphilbolite           Amsden Chert           Amy Creek Chert / Dolomite           Ancaster Chert Lockport Chert and Goat Island Chert         Anchor Point Wood           Andesite           Angel Agate           Angel Island Sandstone           Angel Wing Agate           Aniakchak Volcano Wood           Animikie Chert           Animikie Silicate           Anna Chert           Annadel Obsidian Annadel Farms Obsidian and Annadel State Park Obsidian         Ansonia Gneiss Miller Mine Gneiss, Tyler Lake Gneiss, Siscowit Gneiss         Antelope Chert           Antelope Jasper           Antelope Pass Wood           Antietam Quartzite Antietam Schist, Erwin-Antietam Quartzite, Erwin Quartzite         Antioch Wood           Antique Pink Agate Bubblegum         Anvil Chert           Apache Canyon Turquoise           Apache Creek Agate           Apache Jasper Hickoryite         Apache Mudstone           Apache Turquoise           Appekunney Argillite           Apple Hill Creek Cobble           Aquia Orthoquartzite           Aragonite           Araucarian Picture Wood           Araucarioxylon Arizonicum Wood           Arbuckle Chert           Arcadia Ridge Orthoquartzite           Arenaceous Silicified Siltstone           Argentine Chert           Argillite           Arikaree Silicified Volcanic Ash           Arizona Agate           Arizona Banded Jasper           Arizona Ruby Jasper           Arkansas Novalite           Arkansas River Chert           Arlington Chert           Armuchee Chert Hourse Leg Creek Chert, Frog Mountain Chert         Arnolds Valley Jasper Rockbridge Jasper         Aromatic Bay Wood           Arroyo Jasper           Arvonia Slate           Ash Fork Basalt           Ash Hill Carnelian           Ashwood (Green) Moss Agate           Ashwood Dendritic Chert           Asotin Creek Coffee Wood           Asphaltum Bitumen and Pitch         Athabasca Quartzite           Atoka Argillite           Atoka Chert           Atoka Ironstone           Atoka Quartzite           Atoka Sandstone           Atoka Siltstone           Attalla Chert           Attica Chert Indiana Greenstone, Independence Chert, Wabash Chert         Attleboro Red Felsite           Augen Gneiss           Augusta & Rockingham Cherts           Aurora Borealis Obsidian Fire Obsidian         Avingak Creek Wood           Avon Chert Avon Valley Porcellanite         Ayers Quartzite           Azurite