Gabe,

Mould on wet slabs I control with nothing more than a mild copper sulphate solution. Best to spray all fresh slabs with it and not risk it happening in the first place. Kills it dead, and it can be washed off later, or gets left behind in the chips after the blanks are dressed. It's a wise precaution to take, because some mould will get in and kill the colour right through the slab. Some won't. I can also say from experience, the mould is not good for your chest and general health!

With the aroma, it's not universal, but for example the walnut I have cut from one area in VIC is like nothing else I have ever smelt. Pungent, every tree, every blank. Ditto one area from TAS. One area in EU I have had around 70 blanks from seems the same. Other areas, most areas, it just smells like Euro walnut.