Hello Njo,
Interesting result after cleaning.
The surface looks crystaline in some places.
Especially the pictures from the bottom.
And indeed translucent in some areas.
Based on these pictures I would almost say that it is some kind of stone / marble like material.
Is it heavy ??
Ps. what did the hot pin test do ? Any smell of burned hair
If it is a sort of stone a hot pin would do nothing I guess.
Maybe you can finish the hilt with some dark antique wax an rub that out again. Tha will accentuate the carvings and relief again.
Although now cleaned the carvings look better than before cleaning
Best regards,
Willem