Here's what Penny (Kaley Cuoco) and Leonard's (Johnny Galecki) wedding gift to Sheldon (Jim Parsons) and Amy (Mayim Bialik) really is in The Big Bang Theory. After years of tumultuous dating that included an emotional break-up, Sheldon and Amy finally tied the knot at the end of season 11. This was the CBS sitcom's final wedding following the Wolowitzes and Hofstadters in previous years. Unlike its predecessors, however, the show tackled the aftermath of the ceremony and honeymoon when the show returned for its final season as the newly-weds sift through the gifts they received on their special day.
That included a present from their best friends and next-door neighbors. However, instead of a typical wedding gift like home appliances or other useful things that could make the couple's new life together better, Penny and Leonard opted to gift Amy and Sheldon an obscure looking glass object. The Coopers were initially thrilled about the item since it looked precious and pretty, but things quickly went downhill when they tried to figure out what it exactly does.
Sheldon and Amy's dilemma about the gift was the main plotline of The Big Bang Theory season 12, episode 2 titled "The Wedding Gift Wormhole." Motivated by their desire to learn what the present was without looking like fools for not immediately figuring it out, the pair refused to simply ask the Hofstadters what it was. Instead, they acted as if they knew what it did, wrongly assuming that it was a clue to a scavenger hunt that would lead them to their real gift. While they ran around town excitedly solving the non-existent puzzle, their friends watched them silently in glee. So, what was the present and what did it actually do?
In the same episode, it's revealed that the gift was originally from Howard (Simon Helberg) and Bernadette (Melissa Rauch) who gifted it to Leonard and Penny when they got married a couple of years back. Like Sheldon and Amy, it drove the Hofstadters insane as they, too, didn't know what it was for. Given what they experienced with it, Penny and Howard thought it would be funny to pass it onto the Coopers like some sort of a prank heirloom. At this point, Raj (Kunal Nayyar) butts in and asked Howard if they're talking about the present he gave the Hofstadters when they got married way back in season 3, which was exactly the case. As it turns out, it was a crystal chakra. While Raj didn't get into specifics about what it's supposed to do, Amy and Sheldon learned from Bert that it's made of quartz, which means that for those who believe in the power of crystals, it's supposed to function as a healing stone. It also promotes spiritual growth, awareness, and wisdom.
Admittedly, it's an odd present for a group of friends who works in the scientific field like the Pasadena gang in The Big Bang Theory. It's unclear whether Howard was aware of the crystal did when Raj gave it to them, but if he did, it's understandable why he and Bernadette didn't find it useful. In any case, it was for the best that the Coopers never learned what it really was since Sheldon would more likely be less enamored by it.