I've been gently cleaning the handle of the dagger and have had a very nice surprise.....the 'creamy white' sections are IVORY

There are Lines of Retzius visible (under magnification) on the top surface of the top section of the handle.
The Lines of Retzius....
These fine intersecting lines are visible in cross section, and give an engine-turned effect (intersecting lines with a diamond shape between them) which is unique to elephant ivory.
On Tim's 'rate of exchange' this cost me a little more than a 'fish supper'......and that included delivery