Yes, it´s "Galalith" or "Milchstein". As this product seems to be very fragile even at the time of production it was not widely used.
If the grip is undamaged, a dagger with such a grip for sure has a certain character for me.
Regards,

wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.