The legendary gem drop rate is 100% until you got/collected all the legendary gems in your inventory/stash.
https://diablo.fandom.com/wiki/Legendary_Gems
As a rule, a Rift Guardian will drop a randomly-selected gem if and only if a character does not already have access to all Legendary Gems, where access means that the gem is: (1) equipped by the character, (2) in the character’s inventory (socketed or not), or (3) in the shared stash (socketed or not).
How do you not know this again?
That line there speaks volumes…
Great point. Let players use their brains to figure out which piece of gear is better.
Blizzard, did you know that a lot of people enjoy simple arithmetic? That’s why people buy puzzles!
I feel like Diablo 3 tries to do so much for players there isn’t anything left to do except run and use your skill bar (and pick up loads of garbage to take to the blacksmith, yay.).
This feature is misleading and should be removed. Also, it’s not a fun mechanic. It’s arguably QoL but it depends how accurate it is and on your subjective opinion. I agree that the green and red text should go.
While I don’t think general increase and decrease indicators is an issue with this, I do agree with this overall sentiment and want to say that it is easy to get carried away with what seems like QoL additions to the point that all you are doing is hacking and slashing non stop with no thought outside of combat. That makes for a boring and monotonous experience. Thinking about what loot to pick up and what to do with it (sell, salvage, keep, trade and so on), should be a thoughtful experience. Just picking up every item and dismantling it all is not fun. I personally believe there needs to be a reworked system for crafting. I think gold should play a much larger part, and gold should be much rarer, not dropping all the time from most enemies/breakables. The crafting could be done via gold, a white/magic item of a certain type (crafting a one handed sword, bring a one handed sword), and possibly crafting mats that are rarely found out in the world and obtained through breaking down legendary and rare items, providing more and/or rarer materials through dismantling higher level (or more affixes) items.
So, despite it being “useful” for someone, it can also be very missleading especially for the inexperienced crowd
A bit like item score in BL3
Some newbie kids will see big number/green arrow and throw away their perfect synergizing leg weapon/+skills/what ever not shown in these indicators
As tough as it is to hear, that’s part of the learning experience. There’s a plethora of information out on the internet these days, new players looking to improve have all the tools at their disposal to learn to look past the traffic light numbers. In the age of information, ignorance is a choice.
Item comparison in the UI is one of the most requested features in many games. In WoW there are VERY popular addons that do it and now Blizz has some built in comparisons for basics. Just like in D3, you still have to sort out the other stats to see which is better for your build. It is not all just red and green.
Removing something players ask for in droves, because a few are somehow upset by it, seems illogical.
Here is the article in 2016 talking about the whole development and evolution of tooltip comparisons in D3. Diablo Then & Now – Item Comparison Evolution - Diablo III
“In our current iteration, these stat summaries provide enough information to be useful to the average player and helps shine a light on how each stat contributes to your character’s overall power. This feature was so useful that we received a lot of community requests for a similar overview of follower equipment. In Patch 2.4.0, we fulfilled this request!”
the question is just
why having the lights then?
if its not accurately showing which item is better, they are basically useless
as i said, missleading, so you should ignore them, so they are a waste of resources
So the narrative has changed I see. Either way, again, QoL feature. If certain item has 10 CHC, 67 CHD and the other has 8.5 CHC, 93 CHD, I don’t need to manually equip each item to check which is better.
It is though in your leveling stages. You will not pick up a legendary power instead of damage or survability, that makes no sense at all, unless the legendary power is arguably way better than the stats, but these core stats alone already define how well your combat will turn out to be.
You already can see a comparation of this once you equip the item in your stats sheet, why make a 2nd addition to this “guiding” the player?
It feels dumbed down.
I will repeat:
Yeah, speaks volumes when you already spend time in some GRs to level the one gem you chose cos you liked the end effect of the max rank (25) and then in the next GR you find a next gem which got 50 total ranks to level up a better primary effect, you then switch to this better newer gem and in the next GR you find the next gem which is again better and got a total cap of 100 ranks to max it and so on until you receive gems which require 150+ to be capped, and the rank levels you already invested in the first runs are totally wasted cos you will not use these gems again due the fact of always finding better gems and not being able to save these 4 upgrade points for the gems you ACTUALLY desire, instead the game forces you to spend rank points in gems ONLY AFTER A RIFT you actually might not even use.
Try trolling elsewhere please, or i will flag your next post.
You can level ANY legendary gem you want at any time you want to, genius. What part of that do you not comprehend?
Oh, look, it’s Strolloloin’s alt account with another troll post.
Too transparent hon.
Don’t like the feature, don’t use it. Problem solved.
And what part do you not comprehend that you are forced to level up the first gems you get that you might not even use at all in the future?
Do 20 GRs. Boom, you have all the legendary gems you can get. Level whatever you want at any time you want after that. Geez… 
…so… QoL feature?
4 upgrade points are negligible, barely an inconvenience (wow wow wow wow). GR running is what you do in D3, and it doesn’t take long to get legendary gems you use to upgrade. Besides, BotP is not a bad legendary gem at low level. That you always get it as first.
Thanks for clarifying that i need to waste my time on 20 GRifts.
If the numbers are there to only work with base stats, like it currently does in D3, the indicators are more than fine. For all of us that have played the game and want to figure out the stats (or intuitively know them) there are others who are just starting out (like my 12 y/o on Switch) who those indicators help.
In addition, with the Angelic/Demonic/? (forgot third) power that will be on some (most?) D4 items that baseline stat modifier will potentially mean even less in D4 than in D3 due to how certain bonuses are gated by power and those powers are suppose to impact gameplay some and will potentially not be calculated which would give someone paying more attention on items a “bonus” for paying attention possibly.
In the end the ‘stop-light’ numbers are such a minimal aspect and; honestly, neither add or subtract from the gameplay experience (imho) with veteran players. It helps new players a bit so why not keep them in? I honestly don’t even look at them after like level 20 in a new season, heh.
Your first gem will always be Bane of Powerful. Very useful gem for speed farming. Also, you can always use the upgraded gems that you don’t use it for caldesann despair.
Yes, because supporting each other and logging onto your other accounts to “like” your own posts are the same thing.
Clearly.
Hence my question, why is a legendary gem guaranteed or given for free for each run when i alreaedy started leveling up another?
Its a design issue, just like having legendaries or set items drop after every GR run.
What else to expect of your biased D3 community? 
Not saying everyone is like you but many of you stick to each other like glue.
Even i disagree many times with D2 players.