Sterling silver is chipping off from edges

[srkmag]

I just had a customer contact me that sterling silver item they ordered is chipping from edges and little black showing up.

I never had this happen before and not sure if there is the metal silver mixed with. I generally buy empty blank bracelet, engrave on them, fill color and polish them. My customer is little freaked out telling me item is not sterling silver. I also had in past tested these item for the purity but never had issues and always buying from the same place.

Everything I've read online says only plated stuff will do this. I only use .925, so I'm little confused. Please advise!

Here is the image provided by customer:
10163

[josef1]

Is the bracelet plated even though its sterling if your buying them in sometimes manufactures plate them with a hard chrome like coating?

[china]

Difficult to see from the photo, looks like tarnish (Sterling will eventually tarnish) could be fire scale, could be damage from customer mistreatment, have them return it so you can properly examine the item, if it is customer mistreatment charge to repair it or chalk it up to goodwill if it is fire scale and you have not heated it I would expecting the supplier to replace it

[Aurarius]

I generally buy empty blank bracelet.

What hallmarking exactly is on the bracelets when you get them?