The most well known rare treasure items are Rich Merchant's Ring and Eberunth's Nol, some of you might have also heard about Elviayed, currently there is one known player who managed to finish the whole Elviayed puzzle.

This post is about none of these items, there's another one which is more rare and I don't think it's puzzle pieces were even dropped by someone yet.

Behold, the ultimate treasure item, Crystal of Unstable Darkness, the treasure item which let's you choose a Splendid alchemy stone of your choice.

Let's see what it takes to get it:

In order to be able to craft 

Crystal of Unstable Darkness you'll have to combine:

• 
  Crystal of Depravity
• 
  Crystal of Corruption
• 
  Crystal of Wickedness
• 
  Crystal of Repugnance

Now that we've seen all of those stats let's put them together and see how long it would take to obtain all 4 ingredients:

Crystal of Corruption: 5.7% * 4% * 0.0001% = 0.000000228% @2,000 mastery. Assuming a 1.2 second alchemy time including lag between craft that turns out to ~439,000,000 crafts and 146,000 hours of alchemy or roughly 25 years of doing alchemy 16 hours a day.

Crystal of Wickedness: 0.0001% per grind. With 9s grind time and 100% success rate that turns out to 2,500 hours or 156 days of grinding 16 hours a day.

Crystal of Repugnance: Similar to the last item, 0.0001% per craft. With 1.2s craft time that turns out to "just" 333 hours of solely crafting alchemy stones.

Crystal of Depravity: Since the boxes to turn in are no longer obtainable it doesn't really make sense to worry about this one, but in case Pearl Abyss decides to add them to the current Imperial Alchemy Boxes and leave chances the same: 0.0001% per box @500 contribution points requires you to turn in 1,000,000 boxes over 4,000 days or just shy of 11 years of imperial turn ins.

I think it might be the time to boost these chances a little since playing 16 hours a day for roughly 25 years is a bit too long for 1 puzzle piece for a treasure item, even if it's afk alchemy for most of the part. Not the mention there is not even one publicly known person who has even 1 of these 4 crystals.

I would suggest having a second option for active alchemy where you get mini games which get harder and harder and also increase the chance to get the desired crystal depending on the difficulty you reached on the mini game.

// If I could choose, I would just make one of the crystals to be able to be received if the adventurer could finish a long series of obscure trivia time limited questions about the game, since alchemy is more or less about knowledge, like knowing bottlenecks and how to get certain resources without CM, good luck fighting against the codex. You can also make it so it starts on each region at the same time with the same questions for everyone like once every month during a Sunday or Saturday. A cap like this would be needed otherwise everyone would learn all the questions in less than a week. //

Please rework or buff chances, thanks.