Bling!

How do you LOSE a gaudy $500,000 diamond ring? Ask Nick Young ...

Sean Kingston's got an accessories problem ... someone straight up yanked a $300k chain off his neck ... so claims the singer.

Two suspects approached Sean inside Penthouse Nightclub & Dayclub in L.A. and somehow the altercation turned physical ... they began punching him before one forcibly took the pricey chain -- this according to the police report.

By the time cops arrived Sean and the 2 suspects had split. We're told someone from Sean's camp filed a police report, and an investigation will be launched.

Iggy Azalea drives a hard bargain ... she's also now driving a 1962 Impala that Nick Young has given her as a parting gift.

We've learned that Iggy and Nick struck a deal ... he gets the engagement ring back and she gets the car she had given him for Xmas.

Here's the breakdown ... the ring is 10.43 carats, and reportedly valued at half a mil.

As for the whip ... a '62 Impala is a classic ... a cherry one can go for as much as $100k.

It sounds like Nick made off like a bandit, but here's the twist. In California, and most states, an engagement ring is a gift in contemplation of marriage and if the nuptials never happen, the ring -- by law -- goes back to him.

As for the Impala, it was not tied to the marriage -- it was a Christmas gift -- so he did not have to give it back.

Now you know, Nick ... for next time.

Remember those guys who roughed up Steve Francis and then jacked his chain at a Houston rap show last year???

Well, Steve Francis sure does ... and just implied that the perps got some sort of comeuppance ... and it sounds scary as hell.

Francis spoke with SlamOnline and was asked about the incident, which was captured on video and posted by TMZ Sports.

His response -- "Ask the people who touched me how they feel."

Yikes.

As we previously reported, the chain was eventually recovered thanks to some help from rap mogul J. Prince ... one of the most powerful, well-respected names in Houston.

A 2016 version of the Bling Ring may be prowling Hollywood and other areas where celebs live ... law enforcement sources tell TMZ.

As we reported, Kevin Hart, Chris Brown, Scott Disick and Blac Chyna are among the celebs who have been hit. Our law enforcement sources tell us, there are markers in all of the burglaries that make detectives think the crimes are related.

Most important ... Hart, Brown, Disick and Chyna all run in the same circle ... Kevin not as much as the others. Cops say all 4 were hit when they were out of town. The burglars zeroed in on jewelry and, when there were large sums of cash in a safe, the bad guys knew exactly where to look.

Cops believe the burglars may know their targets, and cops are worried this is just the beginning. We're told the L.A. County Sheriff's Dept. that covers Calabasas and Hidden Hills has put the word out to LAPD's Hollywood division to be on the lookout for the burglars, especially in the hills.

Adrien Broner hasn't hit Floyd Mayweather levels of spending swag yet ... but boy is he trying ... this time dropping a whopping $165k on a diamond & gold neck rope.

We spoke to Joe Avianne of Avianne Jewelry & Co. in NYC and he tells us AB stopped in this past Monday and copped what he called "a pretty serious chain."

What does "pretty serious" look like? Apparently it looks like 14 carats of yellow gold (weighing 1,200 grams), and 130 carats in VVS F colored diamonds.

BTW, we're told "F colored" diamonds are by far the most rare and sought after ... so Broner is kinda wearing a unicorn around his neck.

Miley Cyrus is a serious triple threat ... just check out the merch.

Miley was all smiles with Liam Hemsworth Tuesday night in NYC. It's easy to see why she's got a wide grin ... she's got her man, a HUGE rock and dough pouring out of her purse.

Get it, Miley.

Kevin Hart got jacked of $500 grand when burglars broke into his house ... TMZ has learned.

Law enforcement sources tell us the backdoor to Hart's Tarzana home was pried open over the weekend while he and his family were gone.

We're told the thief or thieves made off with jewelry, watches and clothes.

Kevin -- who was in Miami training with Ndamukong Suh -- came home Monday and reported the theft.

We're told the house has surveillance cameras inside and out and cops are combing through video for a lead.

San Diego Chargers linebacker Melvin Ingram just dropped $22,000 on a RIDICULOUS custom grill ... complete with 700 DIAMONDS ... and TMZ Sports has the pictures.

In addition to the 6.88 carats of flawless, handcrafted diamonds ... there's also 14 carats of white gold.

We talked to Zahir Jooma -- owner of Icebox Diamonds & Watches in Atlanta -- who tells us Melvin LOVED the piece so much he told him he'd "never take it off."

Grill > Mouthpiece

Tony Romo signed a $108 million contract with the Cowboys a while ago ... and it's clear what he DIDN'T spend any of it on ... neck bling ... 'cause the QB got seriously out-iced in Texas Thursday night.

Romo was hanging out with Dez Bryant & 2 Chainz at a party for Dirk Nowitki's Heroes Foundation charity when he posed for this one-of-these-things-is-not-like-the-other picture.

Sylvester Stallone and Rob Kardashian are practically blood bros -- if they bled diamonds and gold -- since Sly just dropped big bucks for a Rolex from Rob's favorite jeweler.

Sources familiar with the deal tell us Stallone hit up celeb jeweler, Nick Bhindi for an 18k white gold GMT Master II -- which just sounds expensive, right? It is.

We're told the diamond and sapphire-encrusted piece set Rocky back just over $84k.

It's a collector's item for sure. The Rollie -- very similar to Rob's -- is now out of production.

Minnesota Vikings speedster Cordarrelle Patterson is showing love like all rich men do ... with diamonds ... blingin' out a custom neck piece to honor the two schools he loves.

TMZ Sports spoke to Albert Bekdas -- owner of Labelle Jewelry in New Jersey -- who tells us CP tasked him with combining his high school and college logos into one kick-ass piece.

That apparently entailed combining 10 carats of diamonds with 5 carats of sapphires into a shiny behemoth that set Patterson back over $15K.

And you thought showing up to the reunion was enough ... slacker.

Kylie Jenner is starting the summer off grilling with a new 18-karat rose gold mouthpiece.

If you recall ... Kylie was gifted a bottom grill by ex Tyga, but like her men -- she's moving on to a new piece.

A source tells us Kylie's new mouth bling was made by Nick Bhindi of Bhindi jewelers.

Normally it'd set the average person back $4,000 and take a week to complete after casting, but for Kylie ... they got it done in 2 days.

Rob Kardashian and Blac Chyna clearly aren't sweating childcare expenses ... not based on the lavish timepieces they just purchased.

A source tells TMZ the newly-engaged couple met with celebrity jeweler Nick Bhindi to pick out his ... and hers Rolexes. Rob opted for a gold GMT Master 2, which is no longer in production, meaning it's worth a bunch. Chyna walked away with 2 rose gold watches.

We're told Rob's was the priciest at around $150,000, and Chyna's diamond-encrusted Rolie was $90k. Her diamond-free one was a far more reasonable $35k.

Ex-Playboy Playmate Ashley Mattingly called the police on a man she says angrily showed up at her home after a year of flooding her with calls and texts.

Ashley, Miss March 2011, tells TMZ ... a guy named Joey claimed to be a DJ and contacted her about doing a club appearance, which she ultimately turned down. Ashley claims Joey kept reaching out anyway -- and even left her a sterling silver Tiffany necklace on Easter.

But according to the police report filed by Ashley, and obtained by TMZ, he showed up at her Orange County home last month and took back the necklace. Ashley called police to report a "stalking," but Joey was gone by the time cops got there.

Ashley wanted the incident documented, but didn't want to press charges.

Joey admits taking back the necklace, but says he's no stalker. Police reviewed text messages and say they didn't see anything threatening.

Scott Disick was hit by thieves where he lives ... and they took a fortune in watches and jewelry ... TMZ has learned.

Disick was in Cannes late last week when someone got into his Hidden Hills home and looted his famous watch collection. Scott has publicly bragged about the timepieces, which include a Rolex Yacht-Master II valued at $32,000. Another watch goes for $48,000.

We don't know how many watches were taken, but law enforcement tells us there were "multiples worth a significant amount of money."