Bleaching

Unique to elves, there exists a condition that leeches their life force and literally drains the color from them, turning skin grey and hair white, leaving eyes a dull black. The Bleaching is poorly understood even by the most knowledgeable elven sages, and seems to strike randomly, impacting elves who are thousands of years old and those who have seen only seventy summers. The best anyone can guess is that it's some sort of spiritual malady, possibly impacting elves from a previous life or decisions made between reincarnations. Most elves who come down with this condition succumb to despair, though whether that's an effect of the disease or because they believe they must have failed their karma is unknown. Only recently has there been any progress in finding a cure.
The dwarven family sent to the old world of the gods has largely completed their four thousand year labor to make the world habitable again, and in so doing discovered deposits of that most precious material on Kytheria: amber. The gods' old world is comparatively rife with the stuff, and the dwarves found so much they felt comfortable experimenting with it. Through trial and error, and the presence of an elf recently come down with the Bleaching who happened to be delivering trade goods, the dwarves made a remarkable discovery: burning amber drives away the Bleaching. The reason for this isn't clear, but the connection between amber and Bleaching is well known; the total number of elves born with amber Marks number less than a thousand, and not a single one was afflicted by the Bleaching. Amber Marks are not only incredibly rare but rumored to speak of a link to the gods themselves, as though elves so born were earmarked to become gods at some point in their lives (or death). Some believe that elves who start Bleaching were meant to be on the path of ascension, but failed some test or let down the fates in another way, missing their chance.