People are missing my points - never mind.
First of all, I would not throw away something valuable, and anything I confiscate would not be simply given back to the pupil the same day.
Secondly, in this case, there are going to be two sides of it, and it is important to consider the other side before doing anything. It is highly unlikely that the teacher threw something in the bin, let alone as the first line of sanction - highly unlikely. A more typical route would be to tell the child to remove the article and put it in their pocket/bag. If the child refuses or removes and later replaces, then it would be reasonable for the teacher to keep the article (put it in her drawer, for example). If valuable, then send it to the office for safekeeping.
The parent also has to consider what to do next, and consider the impact that whatever she does on the child's education for the rest of her time in that class, and perhaps in that school.
Going to the head, full of anger and making demands, is unlikely to be helpful for your child. Letting your child have ingrained that the teacher has no right to do this or that could have consequences throughout her schooling. Think twice, act once.