I read an article some while back in American Woodturner which caught my attention, the article was by Scott Grove and was titled "Creating Geodes in Wood (AW October 2018).

In the article he shows how to create a project from a fairly simple bowl and end up with what I thought was a really nice looking project, so as a break from the normal output of bowls and pots (hollow forms to you) I thought "why not!". So for a start this (apologies for the image quality) is what we are aiming at:

Geode Scott Grove

So I selected a piece of fairly bland timber, in fact a piece of tulipwood I had been given by a friend - yes I actually used a piece of imported timber!! The simple explanation here is that I actually seldom have a blank small enough and I don't want to create waste by cutting up a larger blank and of course as you all know I will NOT split up a nest ...ever, don't even bother to ask!! 

So in terms of the bowl turning initially it is not actually much of a major issue, the critical thing is to get the rim flat and level and you do need to have the wall thickness even across the piece so get the bowl calipers out (or in my case scissor calipers) and make sure. You can cover up minor inconsistencies later on but big variances are really going to show up so from that perspective it does need a bit of patience.

The bit I struggled with was the marking out of the piece, I tried several times (lots of swearing) and did eventually come up with something like the shape I needed but I think that was more by luck than management!

Anyway I have ended up with the bowl being cut and then reassembled. I will now locate a source of calcite and see if I can borrow an airbrush to see if I can complete the project.

As I said none of this was my idea so thanks to the AAW and to Scott Grove.