Our Most Popular Ask-a-Geologist Question…..EVER!

GeodesThis has to be the most-asked question we receive here at Mini Me Geology.  There must be a middle school or high school text book or worksheet out there that is used by many schools in the country.  I think the question is worded a little funny, but here is the question and answer.  For all of you teachers out there, take a look at this question….I think the weird wording is throwing the students off because I have been asked this question (worded exactly the same) dozens of times!

Question:  What are the hollow ball-like objects, such as quartz, which are found in sedimentary rocks?


Answer:
  By “hollow ball-like objects” I believe you are thinking of geodes. Geodes are round in shape and hollow in the center. Geodes are usually filled with crystals such as quartz and amethyst.  This photo shows several unopened geodes and some that have been cracked open with a rock hammer.  The open geodes show the layers of quartz on the inside.  Geodes form when an opening (hole) is present in a sedimentary or sometimes igneous rock.  Silica-rich waters fill the opening and begin depositing agate and quartz crystals into the opening.

To purchase your own geodes, visit the Unique Rocks & Minerals section at www.MiniMeGeology.com.  You will receive a set of 4 large (2″+) geodes that you can crack yourself.  Full instructions for both cracking the geodes and doing it safely are provided. 

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