How would one make a non-toxic pen out of osmium? Osmium is the densest element in the periodic table. However, it is toxic in its pure form. Is there a way to create a standard pen out of osmium but coat it in a dense material that isn't toxic to have the heaviest pen?

How would this pen be made?

It would be a cap pen (like the Uniball pen pictured below) with no wasted space for plastic mechanical parts.
Osmium alloys with many metals, so it could be covered by an alloy. Osmiridium, an alloy with iridium, is even harder than pure osmium.

It would seem possible to dip the osmium pen blank in an iridium or osmiridium bath (at rather high temperature) to produce a long-lasting casing, rather like dipped chocolate cordials.

If you accept this answer, I'd be glad to receive an award of one of these pens. ;-)