I was a rockhound as a kid, so I love this cake.  It's made it's way onto Facebook and into the Huffington Post.

http://www.intricateicings.com/#!Amethyst-Geode-Wedding-cake/cyrp/56a2bc490cf2009838b8080e

wow -- this is amazing just amazing -- i'm so impressed -- thanks for posting, magda

Beautiful cake!  It looks like someone combined an edible geode technique with a cake to make this.  There are a few great tutorials on how to make the edible geodes.  What a unique idea to then carve a cake to place it onto it. I have had the video with edible geodes book marked.  Check out this wonderful video:

Nice!  Thanks for the video link.

This is a beautiful cake!  How do you get the large geode to stay on the cake side?  I know you have to carve the side, but, after you've put the fondant on? carve before and then fondant, then "glue" the geode to the side?  I've see the great tutorial on how to make a geode.  I'm guessing you'd make a shallow one.  I want to make this for this weekend! Anyone know how to do this?  Step by step?  Thanks in advance for your help.

so, I guess I should have scrolled all the way down when I looked at the link.  Bought the tutorial. Awesome! Thank you Rachael!

Whoa, that's cool!