I decided to max out quality on a flintlock for my rogue and use diamonds to reroll DPS higher. Started with a 39.1K weapon at 4% quality. Bumped up the quality to 24% and used a diamond a few times. Got it to something like 59K or maybe even 61K. Man, was I excited! Put the last 1% of quality on it, so that it was at 25%. Used a diamond, and…it went to something like 35.5K and would NOT go any higher, even with increasingly desperate and unbelieving rerolls with diamonds. WTF!? Got so pissed off I just deleted the weapon. Can anyone explain what happened? Seems I obviously did not understand properly how things work.
I can’t say for sure because you dind’t show weapon, but probably was because you reroled Weapon DMG affixes and them become lower than before.
diamond doesn’t work on weapon quality, and it doesn’t directly have an effect on DPS. diamond changes the values of all affixes on an item, except for set affixes and anything on an Eternal item. as @luisfsk mentioned, if you had affixes that affects your DPS in some way, when diamond is used, it is changing their values. so if you had attack speed +10.2% and +78.3% weapon damage %, using diamond might change them to attack speed +9.7% and +77.4% weapon damage %, lowering your DPS. if the values were maxed out, you would only be lowering your DPS. of course, there is a chance of getting higher values, up to an affixes cap/max, but diamond is very random. diamond should only be used on items with Legend and/or Crystal affixes. if your item is lower than 100, increasing the items level will increase the values of affixes a little bit, but this method is only good if you really want that weapon and don’t want to have to make another one when you get to level 99.
Peridot the weapon to level 100 then use diamond if you have a potentially great weapon or just get another as golem says
I believe OP is refering to the use of emerald to increase item quality and at 24%, the chance of getting max affix stat with diamonds was lowered.
Perhaps he was getting higher weapon dmg % (legend affix) at item quality 24% than 25%.
I’ve been testing something similar too, except I kept everything at 5% item quality with 5 emeralds.