Heart of the Aspects

The Heart of the Aspects is a luminous dragon born of the radiant energies of the Dragon Soul artifact. With a glow said to be the equal of a thousand suns, this drakes' blinding light is much like attacking a foe with the sun at your back.

This mount is directly purchasable from Blizzard. Released on February 14, 2012, it is the first dragon mount to ever be offered in this way, and the third overall.

Source
This item is available for purchase from the shop or the In-Game Store for $25 or €25. It was released on February 14, 2012.

Mount Journal
''You are Azeroth's true guardians and the future of this world is in your hands, for the dawning of the age of mortals has begun. - Alexstrasza''

Glowing with inner light, this luminous flying dragon defies the darkness.
 * In-Game Store

Eye-catching air superiority - ''When attacking from the air, it’s best to advance from the angle of the sun so as to blind your foes. Or, just ride a luminous dragon that glows like a thousand suns. Either way, you’re good.''
 * Blizzard Shop

Mail
Players are mailed this mount by :

Notes and trivia

 * Before all flying mounts could swim underwater, the Heart of the Aspects was the only dragon mount capable of doing so.
 * When in water, it will tuck its wings to its sides.
 * Its mountspecial is a backwards loop.
 * Although it has legs, it apparently has no stand,walk or run animations, hovering even at ground level.
 * When it moves, it leaves a trail of streaks and lightning bolts from its wings, and it also has eletricity sparks above its head. Other parts of its long body also glow.