G is for Geodes

I was going to write about gold here, but this is more interesting and there are some facts here that I bet you’ll be surprised about.

Unopened geode - see how plain this is

This is a geode sliced open.  Sorry this pic is in black and white

Geodes are agates that got their name from “achates” because the first one was found near the river Achates in Sicily.  Agates come in a wide variety of colors and patterns.  One must be careful buying them because this stone is easy to dye and the bright, gaudy ones aren’t natural colors.

A geode slice

But how they form is the really cool thing about agates.  They occur as a cavity filling in lava.  If a bubble of gas forms in the lava when it hardens this bubble fills up with silicates.  This is called geode.  You can buy whole geodes, which look dull and like a lump of rock but once opened they glisten with quartz crystals, which can be in many beautiful colors.  It’s truly a feast for the eyes that something so stunning can be on the inside of something so plain and ordinary. 

Here are more sliced geodes

I’m sure many of you have seen these around in souvenir shops, or at gem fairs.  They are strikingly gorgeous and make good bookends, or a conversation piece to sit on a shelf.

And look at this one.  Isn't it pretty?

You can also buy flat “slices” of geodes, which show patterns to their best effect.  When the geode fills up sometimes it hardens in layers of different colors.  If there’s a gap more quartz crystals may grow.  These flat pieces make excellent jewelry.