Magnifiers

First, it depends what you want to do with the glass.

If you want to "get a feel" of a coin, a very low magnifier is great - 1.5x to 3x. These are the old-fashioned "sherlock holmes" magnifiers and can be had in any hobby store.

For checking cracks and crevices, you really don't need anything more than 10x. Look for "jeweler's loupes" or just "loupes" on e-bay and that will get you going.

If you're looking for errors or varieties, then you know what you're looking for and will see it in hand or at most 10x. Then the error hunter might resort to various magnifying devices that go anywhere from 20x to 200x.

One of the more popular high power devices is the QX3 or the new Qx5.
Here's a link to it: https://www.microscopy-uk.org.uk/ma...4/dwqx5.html