Need help to identify this hand lens and where I might be able to buy more like it.

A colleague of mine uses this old hand lens for looking at rocks (we're professional geologists). Honestly this thing is basically cheating, you can see so much compared to the usual hand lens sold which typically have a diameter of 18-24mm and 10x magnification. This thing has a diameter of 36mm, an amazing field of view, and I'd guesstimate would be in the 10-15x magnification space.

What is this style of lens called? The only thing I know is that it was used by a previous family member who was a jeweler. Any help to find a similar lens I could purchase would be amazing.