Zuckerberg, whose stake in vested Facebook shares is worth roughly $11 billion, announced plans in 2010 to give a $100 million gift to the beleaguered public schools of Newark, New Jersey.
The gifts are part of Zuckerberg's involvement in The Giving Pledge. Launched by Microsoft founder Bill Gates and investor Warren Buffett in 2010, the group asks U.S. billionaires to give away at least half their wealth during their lifetime or after their death and to publicly state their intention with a letter explaining their decision.
Zuckerberg said on Tuesday that he made a contribution of 18 million Facebook shares to the Silicon Valley Community Foundation to "lay the foundation for new projects."
At Tuesday's closing price of $27.71 per Facebook share, the gift translates to $498.8 million.
Zuckerberg founded Facebook in his Harvard dorm room in 2004, turning it into the world's most popular online social network with roughly 1 billion users. With its high-profile initial public offering in May, Facebook became the first U.S. technology company to debut with a $100 billion-plus valuation, though questions about its long-term money-making prospects have pressured share prices.