LeBron James Knuckles Up ... with CHAMPIONSHIP RING!

It took 7 years ... and a team loaded with All-Stars ... but LeBron James finally got his NBA championship ring last night -- and he couldn't wait to show it off.

James and the rest of his Miami Heat teammates received their jewelry right before last night's season opener against the Boston Celtics ... it's pretty nasty.

Here are the stats:
-- Weighs 115 grams
-- 14 karat white and yellow gold
-- 219 DIAMONDS!!

For the record, LeBron's ring size is 13.5.