Proper sealant for popup? (faux marble)

I need to know the best or acceptable sealants for a drain popup in a faux-marble sink.

I had to replace a broken sink drain popup last week. When I read the plumbers putty can, it says emphatically not to use it on plastic or "marble." Short on time, I found a used tube of old white "silicon II tub & tile caulk" and applied a bead around the drain opening before installing the popup tube. Then I let it cure 3 days. (I must have confused it with acrylic or blended material.) Today, I find the sealant is still not cured, as the fillet is smearable around the edge of the metal collar. Bummer.

Looks like I need to replace the stuff with acrylic sealant instead --that looks like what I had used before. I don't trust the thin rubber gasket in this kit. But what is the real problem with plumbers putty anyway? Does it attack the phony marble or just stain it?

Use either Silicone RTV (GE Silicone II kitchen & bath) or, Sta-Put Ultra Plumbers Putty. Regular Plumbers Putty has oil in it which will stain marble.

If you use Silicone RTV clean up the excess with denatured alcohol.

Thanks, Redwood...

Oddly, that GE silicone II sounds like the same product I used but it must have been too old to cure properly. (5-10 years, maybe??) Off to the store...