These are two different types of wood from Australia.
They are both desert growing trees from the Acacia family. Koa is probably the best known type of Acacia.
Growing in desert conditions leave these woods with a hardness and density comparable to desert ironwood.
The top pair in this photo are True Mulga (Acacia aneura)
The bottom pair are Gidgee (Acacia cambageli)
Gidgee with curly figure is called Ringed Gidgee.
The Mulga was a wood my supplier suggested that I try.
It is not very dramatic. A bit more on the conservative side. The fiddleback figure becomes a lot more pronounced when it is sanded finer. This is a popular wood with the Australian knife makers.
The Ringed Gidgee is the ultimate knife handle wood (in my opinion).
Kind of like a cross between ironwood and koa. The piece in this photo is a light color example with others in darker browns. This stuff is really hard but easy to work and finish. Even smells good when you are sanding it.
These are some of the wood I recently received from Western Australia. When I got the wood it had been kiln dried.
But....... when I split a block the moisture reading in the center was about 16%. Not quite as dry as I like.
I put the wood in my dehumidification kiln and now it looks like it is about ready. I will be putting some pieces in my webstore in the coming weeks.