Yeah the 21" sun monitors we had in school were trinitron. I remember they were heavy for a 21" monitor (shielding?) and the degaussing on startup would induct into an adjacent monitor. (I was a sysadmin for a Sun heavy CS department in the 90's.)

I'm pretty sure Trinitrons are always heavier than other monitors of equivalent size because of the aperture grill design. It let's more light pass through, making them brighter, but boy do they get stupid heavy as the size increases.

Yes, the aperture grille (hundreds of wires and a metal frame holding them in tension) is itself heavier than a traditional shadow mask.

However, aperture grilles also use differently-shaped glass from shadow masks. The screens are only curved horizontally like a cylinder rather than on both axes like a sphere. This requires thicker, heavier glass to hold the vacuum.

Later flat-glass shadow-mask tubes were much closer in weight to flat Trinitrons.

so was I, and HP and AIX a bit too (Urbana-Champaign college of engineering, for a couple years)

all the sun displays were built by Sony afaik, so you're probably not far off.

Yup! I had 2 x SUN GDM-20E20 hooked up to my desktop in 1990-something. They were Sony screens and they were so clear & bright. They weighed a ton however and even broke a cheap desk I had.

SGI also used rebranded Trinitrons. My first job out of college I had an Indy with a giant (for the time) Trinitron on top of it. Don't remember the exact size except that it was bigger than 17", so probably 19" or 21".