Featured Question about silver

Hi all being new to all of this I was hoping someone could clarify a couple of things. These bangles were in a cheap bag I brought. Now the 2 silver ones scratch test as sterling haven't got my gold test kit yet so not sure about that one. Question is these aren't marked and are quite heavy. Is it a practice by some countries not to mark them internet says something about southwest not marking. They may be asian but who knows quality looks ok to me anyway. And if the other is gold that has no marks either would that be from same area.
Is there any plated silver that would pass the acid test also.

 

Many countries don't mark, it is not mandatory everywhere.

In 1972 an international convention for the quality of precious metals was set up in Europe, called the Hallmarking Convention (HMC).
More and more countries are joining, also outside Europe (not all European states are member). They have to have a strict controlling system and trustworthy marking system.
There are some aspiring members, especially among the major jewellery producers like Sri Lanka. The aspiring members are working towards the convention standards, often doing a very good job.
Members are allowed to use the mark of the convention, a set of scales. This one is for sterling:

 

If something is heavily plated, it will pass the acid test. You'd need to cut very deep. Are they magnetic?

 

Thanks for info guys. If that' the case I wonder how many sterling items are sitting in op shops etc because they aren't marked more to look for.