I normally recommend against laser bonding marks on silver. Over the last almost 20 years of working with laser bonding materials such as TherMark and CerMark I have found silver to be the most difficult metal to mark.
For some reason in general on silver items I have marked the ones from North, Central or South America tend to mark better. Silver from India and Asia tends to not mark as well. I am not saying that other parts of the world are making lower grades of silver or anything like that. It might just be something like there is more magnesium or some element in general in silver from certain parts of the world that allow it to mark easier.
Silver conducts heat away very fast so you will have to mark with a lot of power and very slow speed normally to get a mark.
The best versions of CerMark for silver would be Ultra or LMM 14 not 6000. LMM 14 has an aggressive ph balance to it especial in liquid form and it may stain or tarnish the silver. We have not had a chance to directly test silver with the Ultra yet but it works well on other soft metals and should not cause satins.
Silver is very soft and if you are able to make a good laser bond on it the mark is basically as strong as what you are marking on. If the mark was for a necklace pendant that just hangs it should be fine but if it is for a ring, bracelet or keychain type item that will see wear I would avoid it. What most people don’t understand is that the silver wears down and if it is just a kind of plain peace you won’t notice it much but if there is a high contrast mark and that wears then it is much more noticeable.
Silver plating can be even more of a problem because you never know how thick it is or how consistent the thickness is from part to part. There is a potential of the heat from your laser possibly melting through the plating if it is thin.