You are almost certain to want a diamond saw also. Many times the only way to trim a piece is to saw it thin so you have a slab with the crystals on top and a sawn surface below, then use a trimmer to trim the slab. You never want a sawn surface exposed in the final mount, but a sawn surface below is ideal.
The best trimmers currently available are from Swarf systems. You should buy their T6 unit, which is more or less the same size as the old Meister trimmer. A big T10 is available, but most people won't want something that big.
If you are well heeled, consider a Zuber trimmer. These are fantastic, made in Germany, and use a custom designed hydraulic system. The only real drawback is the price (currently just short of $1000). Also in time after hard use, the seals may need to be replaced which is a big and tricky job.
Ann Meister 840 E. Mendocino St., Apt B5 Altadena, California 91001 phone (cell) 626-222-7914The problem with Meister trimmers is that people tend to abuse them and push them beyond their limits. The end result of this is stripping out the threads. Mine ended up like this, and I have a second one that was given me in hopes that I might fix it. It also had the threads jammed up and ruined.
This link describes my repair work:
The offer a mid-size unit with a $500 price tag. I find this an inconceivable purchase. If you buy one, don't say I didn't warn you.
Foremost in this category is the Yost trimmer, which came before the Meister and is a bit smaller. The Yost trimmer was the original from the 1960's and is a screw type trimmer, well made and legendary. Copies were made in the 1990's with aluminum parts. These are simply not up to the job and should be avoided.
Tom's Mineralogy Info / tom@mmto.org