These two achievements require crafting a Radiant Star gem of the four original types: topaz, ruby, emerald, and amethyst. Finding the recipes is no longer an issue because in the 2.0.1 patch, all gem recipes through Marquise were automatically trained (or gained on jeweler levels – mine started at 10 so I can't check). So, prior to the expansion, one could farm hundreds of Flawless Square gems at level 60 and slowly work their way up to a Radiant Star.
Unfortunately, once you hit level 61, Flawless Squares no longer drop. Only Marquise and Imperial gems do.
Given the very small window where Flawless Square gems are eligible to drop, the high number of gems required, and the low amount of experience required to get out of this range, is there any reasonable method for acquiring these two achievements in RoS?
Best Answer
I think(not 100% sure) that you can get a lot of Flawless Square gems with help of one of your friends(or multiboxing).
A level 60 character should create a game. A level 70 character then joins. When level 70 character is in the game, level 60 character leaves. Level 70 kills everything. The game level will stay at 60 as long as host will remain level 60(which will be the case because he won't get any levels).
And as you said, Flawless Square gems stop dropping at level 61, so try not to get any experience with that level 60 character for as long as possible.