No. The term geode is used to refer to a cavity or vug in sedimentary or igneous rock that is lined or completely filled in with mineral deposits or crystals. These deposits are formed from the mineral rich water that enters the cavity. It is more mineral crystal than rock.
They aren't found in igneous matrix only. Agates are formed in gas cavities in volcanic rock, as well as in cracks and holes in metamorphic and sedimentary rocks. Solutions high in silica content filled these cavities to form silica gel which hardened to the agate we know.
Generally, the formation temperatures are now thought to have been between 40 and 270degrees centigrade, perhaps more to the lower end of this range. Theory of agate formation has evolved with better microscopes and continued study over the years. Books by Roger K. Pabian are recommended.
At any rate, there were no human witnesses to the formation of agates, and we are still learning about these fascinating gems.
yes it is a common and widely occurring type of intrusive, felsic, igneous rock
Agate is a mineral.
yes
Sedimentary rock can be made up partially of igneous clasts, but igneous rock is igneous rock.
igneous (extrusive)
Igneous, examples include Granite and Basalt
Onyx like agates is a crypto-crystalline mineral and so it doesn't have any cleavages developed.
Cooling and solidifying magma turns into igneous rock.
Agates are none of the above rock types, but a form of the mineral quartz, normally formed as a gas vesicle filler in igneous rocks, the microcrystalline quartz gradually filling the cavity with successive layers.
semi precious
This site will explain:* http://cash-and-treasures-wiki.travelchannel.com/page/Origin+of+Agates?t=anon
Agates can be found in various places around the world, including river beds, volcanic rocks, and areas with geothermal activity. Some popular locations for finding agates include the beaches of Lake Superior in the United States, the coasts of Brazil and Uruguay, and the state of Gujarat in India. Additionally, agates can also be found in certain regions of Australia, Mexico, and Germany, among others.
Botswana.Because theres an agate called botswana agate and also they can be from Wyoing, madagascar,under the sea. ANSWER: There are many beautiful agates to be found in Lake Superior. They are easy to find too. Just wade in and pick up the objects that reflect the sun and look very bright and shiny. These will be agates.
Moss Agate and Turritella Agate
somewhere... near a volcano or dormant volcano
eBay is one place.
600$
Tennessee Agates are primarily found in the areas surrounding the Cumberland Plateau in Tennessee, United States. Some specific locations include the counties of Smith, Warren, and White.
People with money they seem this is a pretty stone
Beaches and gravel pits are popular spots to look. Try to find a local gem and mineral club to learn more, or find the book on Lake Superior agates.