I know what a geode is I mean is it igneous metamorfic sedementary or what?
2007-09-03 16:56:11 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
Geodes are partially filled gas cavities from a lava flow, commonly filled with silica (SiO2) in a form of chalcedony. When the cavity fills completely it is called agate. The lava flow that produced the geode is an igneous event but the infilling of minerals (silica, calcite, quartz, etc.) is a metasomatic event (changes in mineralogy due to water under a wide range of pressure/temperature relationships). Metasomatism is a type of metamorphism, which makes geodes metamorphic rocks.
2007-09-04 04:31:57 · answer #1 · answered by Amphibolite 7 · 0⤊ 0⤋
The igneous variety are formed from the ancient volcanoes. That is the West Coast of North America, Mexico and Brazilian geodes. The sedimentary geodes are formed from gas and air pockets as well, but sometimes the pockets formed from decaying prehistoric plants or animals that released a gas as they decayed. These are the geodes found in the Midwest, Indiana for instance. Our geodes are of the sedimentary variety, and they are more varied and different than the igneous volcanic variety.
2014-03-01 13:54:19 · answer #2 · answered by charlesesnider 2 · 0⤊ 0⤋
Geodes (Greek geoides, "earthlike") are geological rock formations which occur in sedimentary and certain volcanic rocks. Geodes are essentially rock cavities or vugs with internal crystal formations or concentric banding. The exterior of the most common geodes is generally limestone or a related rock, while the interior contains quartz crystals and/or chalcedony deposits. Other geodes are completely filled with crystal, being solid all the way through. These types of geodes are called nodules.
2007-09-03 17:24:19 · answer #3 · answered by _Me_ 1 · 0⤊ 0⤋
Geodes are formed from igneous rock, Volcano bubbles. Inside is quartz.
Here's a more informative page.
http://skywalker.cochise.edu/wellerr/students/geode/Geodes.htm
2007-09-03 17:05:52 · answer #4 · answered by Somewhat Enlightened, the Parrot of Truth 7 · 0⤊ 0⤋
What Are Geodes
2016-10-06 10:07:32 · answer #5 · answered by ? 4 · 0⤊ 0⤋
Basically a hollow rock that has crystalized minerals inside. Very beautiful and interesting to look at. This article should help with what sort of rock it is:
http://en.wikipedia.org/wiki/Geode
2007-09-03 17:00:29 · answer #6 · answered by kcpaull 5 · 0⤊ 0⤋
Goedes are rocks that have crystal formations in them.
2007-09-03 17:00:46 · answer #7 · answered by beanhead1972((14HIM)) 6 · 0⤊ 0⤋