Great stuff Dan...!
Those "bits" of Olive wood are as rare as money in my pocket and from the nature of things, where the Olive tree develops these treasures inside of it, are very deep within the wood and often where most of the "movement" will occur when cut out and put to dry.
On the other hand, those "faults" allow for one's imagination to put into practice some of the best features one can add to a beautiful piece of wood like that, there are too many options to consider but, I found that one of the best filling materials to used in these cases, is the crashed precious stones, with turquoise on the top of my list.
There are many places now where these crashed stones can be found for sale, they have various crashing grades, from chunky to fine powder and everything in between however, you find 2 types, the natural rock and the man made stuff, both identical but the natural rock will destroy your HSS tools if the chunks are big so carbide tools are a must.
For effect, the bigger the chunks the better and when possible, use a combination of sizes if the filling whole/crack will allow, the finest the the material the less impressive will be, with not a lot more than just a solid colour showing, while the coarser stuff leaves a great stone effect ...!
Anyway mate, I like what you did whit that blank, thanks for showing and mentioning, from where you got it from...!
Cheers
George