If you check the label on your plumber s putty you should see a note that says something to the effect.
Can you use plumbers putty on cultured marble.
Stain free plumber s putty on granite marble quartz sandstone and other natural porous materials.
Sta put ultra plumber s putty is designed for use on granite stone marble and other porous surfaces.
I recommend that you use silicone.
Stuff that is more porous than stainless steel or whatever.
For setting frames faucets and basket strainers use this oatey 9 oz.
Do not use on cultured marble.
However you do need to provide a sealant between the drain and your new cultured marble sink.
They sell two types of plumbers putty one that is stain free and is for use on stuff like marble granite quartz etc.
However if the damage has already been done do not worry.
The stain can be removed through a marble cleaning technique known as poulticing most of the marble used to create kitchen counters is synthetic or cultured marble not true marble.
Plumber s putty can and will cause staining on any of the cultured products such as cultured marble granite and onyx.
Plumber s putty creates a waterproof seal around fixtures and faucets.