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Geology/crystal formation identification


Any info i could get on this would be great !!!

The picture is blurry but my guess without more through investigation is at the strange rock that you have is a geode.  

Geodes are geological secondary structures which occur in certain sedimentary and volcanic rocks. Geodes are generally, but not always, hollow spherical to oblate masses of mineral matter that may form from either the filling of vesicles (gas bubbles) in volcanic to sub-volcanic rocks by minerals deposited from hydrothermal fluids, or by the dissolution of sedimentary or concretions (that were deposited syngenetically within the rock formations they are found in) and partial filling by the same or other minerals precipitated from diagenetic or hydrothermal fluids. Geodes differ from vugs in that the former were formed as early, rounded, structures within the surrounding rock, whereas vugs are irregular voids or cavities within a cross-cutting formation, usually a vein or breccia. Geodes also differ from "nodules" in that a nodule is a mass of mineral matter that has accreted around the nodule nucleus. Both structures had the minerals contained within, deposited from groundwater or hydrothermal processes. Geodes commonly have a chalcedony (cryptocrystalline quartz) shell lined internally by various minerals, often as crystals, particularly calcite, pyrite, kaolinite, sphalerite, millerite, barite, dolomite, limonite, smithsonite and quartz, which is by far the most common and abundant mineral found in geodes. Geodes are found mostly in basaltic lavas and limestones; but can occur in sandstone or shales.

Most geodes contain clear quartz crystals, while others have purple amethyst crystals. Most geodes are made of some type of quartz, (amethyst, agate, chalcedony,jasper, etc) but occasionally crystals such as calcite, dolomite, celestite, etc. Your's appears to be quartz.  There is no easy way of telling what the inside of a geode holds until it is cut open or broken apart. However, geodes from any one locality usually have a more restricted variety of interior mineralization.  
Geodes and geode slices are sometimes dyed with artificial colors. Samples of geodes with unusual colors or highly unlikely formations have usually been synthetically altered.


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Joe Norris


I am an economic geologist. An economic geologist does mineral evaluations and appraisals of mineral or mining properties. I can tell you if your deposit has value - remember that a mineral deposit, no matter how good, only has value when mined. Any value assigned to a mineral deposit, in the ground, is only the speculative value that deposit.


I have been a economic geologist for most of my 35 year career. Although I have done work in perhaps 45 states and numerious countries much of my work has been in Appalachian coal, intermountain west gold and silver, and Arizona uranium.

Past President of the Virginia Section of the American Institute of Professional Geologists and a certified geologist in twelve states.

BS Degree from Eastern Kentucky University. Work on MS Degree @ Eastern Kentucky University, Colorad School of Mines & Marshall University Numerious short courses on the value of mineral deposits and how to value same. Also several short courses dealing with the different types of geologic processes; sedimentary, igneous, metamorphic along with the mineral associated with each.

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