Diablo 4 brought back the series' strangest gem, and it keeps talking
It moos, talks about Hell, posts cryptic numbers, and even got Joe Shely talking about Diablo again.
Diablo 4 Season 15 has brought back the 
Chat Gem, which was previously a relic in Diablo 2. However, this version appears to be a lot more talkative than the original! Players have seen it activate itself, make cow noises, post strange numbers, and even send messages about Hell...
Many theories are going around about this gem, with the most talked-about one being that it could open a secret level. Originally found by a player while running a memory dungeon (the Season of Hell's Legacy added dungeons in the style of different Diablo games), the community has been discussing this chat gem a lot, and we now have a bit of a better idea of where it comes from and what happens after you equip it.
The Gem Comes From a Diablo 2-Style Room
Reddit user lanyere believes they found the Chat Gem inside a Diablo 4 Cornerstone Dungeon, one of Season 15's Diablo 2-inspired seasonal areas.
According to the player, the dungeon was simply a rectangular room with a gem in the center. There was no boss or combat encounter, and picking up the gem completed the dungeon. However, that layout appears to be part of the joke. The original Chat Gem was located inside Diablo 2's Battle.net lobby, where players could click it repeatedly to switch between activated and deactivated states. Its purpose was never clearly explained, which turned it into one of the longest-running jokes in the series.
It Does More Than Say Activated
Once placed inside jewelry, the Diablo 4 Chat Gem begins producing notifications. Reported messages currently include:
Chat Gem Activated
Chat Gem Deactivated
Perfect Chat Gem Activated
Mooooooo
The original poster of this discovery says the gem also sends messages about Hell while they are completing quests. These notifications happen randomly and without a consistent timer, meaning you do not need to keep removing and reinserting the gem to trigger them.
Another player did report receiving the Perfect Chat Gem message after repeatedly socketing and removing it from a necklace, but there is no separate Perfect Chat Gem item or confirmed reward connected to the message.
The Random Numbers Remain Unsolved
The strangest messages are long number strings. At the time of writing this article, the following are recorded:
938548393
500253581
227824619
Those numbers became smaller across that particular sequence, but there is not enough evidence to call it a countdown. A member of the Diablo secret-finding community also reported receiving different numbers with no repeats. So far, they have not found a pattern matching the numerical Chat Gem messages used in Diablo 2 Resurrected.
Even Joe Shely Joined the Search
The mystery was enough to bring Diablo designer Joe Shely back to X (formerly Twitter). On September 18, he asked players to remind him of the correct number of times to click the Chat Gem.
Joe Shely@JoeShely𝕏Can someone remind me—what is the correct number of times to click the Chat Gem?
What makes this even more suspicious is that this was Shely's first visible X post since April 2025 and also his first Diablo-related post since May 2024.
Sure, the Chat Gem could simply be an elaborate Diablo 2 joke, but its cow message and the return of items such as the 
Black Mushroom and 
Liquid Rainbow have led to theories about another Staff of Herding-style secret (even though there currently is no Staff of Herding anywhere in the game or game files). No one has demonstrated that the gem unlocks an area or forms part of a hidden recipe yet...