Cool little item , Serial .
It's 'Asian' in origin , but it is a bit oddly themed for the 'Asian-only' market , however it's looking like a cutie through my eyes .
I don't think you'll like my very best guess (unless you're Japanese & use such facial/beauty products) , Serial , but hey here goes :
IMO
Your item appears to be a mixing vessel for nightingale droppings , as are commonly used in Japan ... such items sometimes come as fancy special 'gift sets' and as such usually have a few extra items nestled within them (in their gift boxes) , such as a smoother (bamboo or shell) , a short-bristled brush , a silk bag full of nightingale poop , a hand-fan & blotting papers/rice chaff bags.
The odd thing to me , concerning the motif of the carvings is depicting the "Nightingale & Rose" , which comes from the title of a "western" poem , rather than the more famous (in Japan) Onoto Watannas' "A Japanese Nightingale" .
I'd also say that your item is very much indended to be given from a mother to a daughter , or from a husband to his wife , as the depiction is symbolic of great love .
As to the patina , well I can't really say , as dyed shell items can be easily 'doctored' to color(s)-of-choice... I'd hazard a guess of the 1970's-1980's , which ain't a real guess , cuz I kaint see the dang thing in front of me in RL !
So there's my 2 yens-worth .
