I realised that the FAQ article https://en.numista.com/help/what-are-the-mandatory-requirements-for-submitting-a-new-item-24.html says:
If the contributor owns the item, the physical properties should also be added: dimensions, weight, magnetism, type of edge, orientation, watermarks, etc. These are important pieces of information that are often not listed in reference catalogues.
I did not know the magnetism was so important:
- As contributor, when I create a new page I add the magnetism only if I do not know the material.
- As referee I ask for the magnetism if the contributor does not know the material.
I write the magnetism in the “Composition > Additional details” field, but the magnetism is important, so I suggest add a specific field. Maybe with options: Magnetic, Non-Magnetic, Variable (if one year is magnetic and another is not), Unknown (default)
Related suggestion (not the same): https://en.numista.com/forum/topic157011.html