Kobe Bryant's 'Best Card In Existence' Sells For $2 Million -

A super-rare Kobe Bryant card just netted a fortune in a private sale ... with TMZ Sports learning the piece sold for a staggering $2 MILLION!!

The card is a 1997-98 Metal Universe Precious Metal Gems piece -- and it's one of the rarest Black Mamba cards in existence.

It's numbered to 100, although only 10 of the emerald version were ever made, and with an 8.5 grade, it's still in ridiculously good condition.

Officials at PWCC Marketplace -- which brokered the sale -- tell us the historic sale went down last week ... saying it set an all-time record for a Kobe card.

"This is arguably Kobe's best card in existence," PWCC exec Jesse Craig said. "It's more desirable than even a Kobe Bryant rookie card or a Kobe Bryant autograph."

The front of the card features a still image of a young Bryant donning his #8 Lakers jersey ... and passing the basketball with flair.

The back of the card displays the Mamba with a focused look on his face ... and his stats from the '96-'97 season.

Craig tells us the card's design is also what makes it so valuable ... because it was one of the first-ever created in the "insert" style mold.

"These Precious Metal Gems variants are arguably the most desired insert card in the entire world," Craig said. "These set the tone for the insert market going forward."

No word on who the buyer is ... but something tells us they're pretty rich.

Congrats on the purchase!