Otherwise, you would want to switch back to a Ruby. Once a Follower has their maximum of 150 CHD, the Emerald in their Weapon is no longer effective, unless the Emerald is part of that 150 CHD cap.

My current thoughts for Followers and Gems (At Level 70 and ~30% CHC): NOTE: They are principally depicted in three forms: as entirely human with snakes on the heads and necks, as common serpents, or as half-human, half-snake beings. Upgrade: +0.3 additional damage per Rank. Stats Bane of the Trapped Legendary Gem Properties: Increases damage done to enemies under the control-impairing effects by 15. It can only be socketed into Amulets and Rings, and drops from Greater Rift Guardians. So now, I’m also considering putting a Diamond in his Helm to see if it does anything for his CDR. Bane of the Trapped is a Legendary Gem in Diablo III. I tried this with the Templar and, sure enough, at Level 70 and more than 30% CHC, he gets more benefit from having a Weapon with an Emerald in it. So, I decided to test this further and this is what I discovered: Just like with our Characters, once you reach a certain Level and your CHC is close to 30%, you want to switch from Rubies in your Weapon to Emeralds. Since I rarely get any Follower’s CHC higher than 20%, I always put Rubies in their Weapon. Last night, I was gearing up my Templar when I noticed I had gotten his CHC to 35%.

Because of this, we usually put main-stat Gems in the Followers’ Jewelry and Rubies in their Weapons. I’ve always read that Followers have caps to their stats.

Diablo 3 follower legendary gem