Holding onto an ex's stuff may prove profitable later on, at least if your ex turns out to be the wealthiest man in the world.

The former girlfriend of tech entrepreneur Elon Musk is auctioning off a cache of photos and Musk memorabilia from her relationship with the billionaire. Jennifer Gwynne, Musk's college girlfriend, is selling the mementos through Boston-based RR Auction.

Gwynne and Musk started dating in 1994 when they both worked as resident advisers in a university dorm, according to a news release RR Auction shared with CNN. Soon after graduating from the University of Pennsylvania, Musk started in a doctoral program at Stanford, but dropped out to launch his first startup, Zip2.

The lot includes 18 candid photos of the entrepreneur as a baby-faced economics student at the University of Pennsylvania, as well as several other mementos of Musk and Gwynne's time together.

The glossy photos show the billionaire looking every bit the normal college student before his meteoric rise to success: goofing off in a dorm room, hanging out with his fellow resident advisers, and cuddling with his girlfriend.

The item with the current highest bid is a signed birthday card, followed by a necklace gifted to Gwynne on her birthday.

“Happy Birthday, Jennifer (aka, Boo-Boo), Love, Elon,” reads the note. As of Sunday morning, the highest bid is almost $7,000. The card is expected to sell for more than $10,000, according to RR.

The gold necklace includes an emerald from the Zambian emerald mine owned by Musk's father Errol, a wealthy South African property developer and engineer.

“When we went to visit Elon's mother in Toronto during the Christmas break of 1994, Elon gave me both the small 'love, love, love' note and the necklace,” said Gwynne in RR's statement. "His mom had a number of these necklaces in a case in her bedroom, and Elon told me they were from his father's emerald mine in South Africa — he pulled one from the case. And because I had not gotten him anything as a Christmas gift (and I felt very guilty about that), he said we would consider the necklace an early birthday present for me.”

“I wore the necklace for a number of years on and off, but it's mostly been in my jewelry box for the last ten years (always reminding me of Elon, of course).”

The necklace also comes with two photos, one of Musk and Gwynne with Musk's mother, the model Maye Musk, and one of Musk and Gwynne at an end-of-the-year formal in 1995.

Tesla superfans can place a bid on a piece of Musk-orabilia until Wednesday, when the auction closes. (CNN)

•PHOTO: A photo of Elon Musk having a drink with his Jennifer Gwynne in 1995 is one of several mementos of the tech billionaire's college relationship up for auction.

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