“Phoenix tears… Of course… healing powers… I forgot…”
-- Lord Voldemort / Tom Riddle in the Chamber of Secrets (CS17)
The tears of the phoenix have healing powers, and are the only known antidote for Basilisk venom (DH6).
The tears of Fawkes the phoenix are symbolic of the healing power of love, the power Voldemort never had. In the books, any character who had feelings deep enough to shed a tear still had the ability to love. True some characters cried easily, such as Molly Weasley, Dobby the House Elf, Rubeus Hagrid, Professor Trelawney, and even Hermione Granger. Others are more unexpectedly emotional, such as Narcissa Malfoy, who completely lost her composure over the fact that the Dark Lord wanted to punish her son (HBP2). Draco was a pureblood bully who willingly took the Dark Mark, and Harry is shocked to see him crying "real tears" in the bathroom and confiding in Moaning Myrtle that he was afraid he and his family would die if he couldn't kill Dumbledore (HBP24).
The character perhaps most closely connected to Fawkes and the phoenix tears is, strangely enough, Severus Snape. When Harry cut up Draco with the dark spell Sectumsempra, Snape knelt on the dirty floor and saved Draco with a counter-curse that "sounded almost like song," reminiscent of the song of the phoenix in the Chamber of Secrets when Harry and Ginny were saved (HBP24). Snape's memories left behind after his death showed Harry that he was devoted to both Lily Evans Potter and Albus Dumbledore and wept horribly after both their deaths. In the Deathly Hallows 3 movie the connection with Fawkes was taken even further and Snape's tears were used literally to convey his memories, showing that he was not an evil Death Eater after all (DH33,DH/f). Snape's ability to love was the "flaw in the plan" that Voldemort never saw coming, and convinced Harry to sacrifice himself to "heal" the Wizarding World.
The phoenix is a creature that burns to death, then rises from the ashes. Snape also died, not killed by a Basilisk but by a reptilian creature just as deadly - the cursed Horcrux snake Nagini. Just as a phoenix rises from the ashes as a newborn fledling, Snape's name rose again with Harry's son, Albus Severus Potter (DH/e), something that definitely brought tears to the eyes of many fans. ~ SIP