In Greek mythology, the Heliades were the daughters of Helios and the Oceanid Clymene (also called Phaethontides). After their brother Phaethon fell from the sun-chariot, they grieved until they became poplar trees and their tears amber beside the Eridanus. Name-lists vary among Hyginus, Aeschylus's fragmentary Heliades, and the Odyssey scholia.
Adapted from Wikipedia, "Heliades" · CC BY-SA 4.0
I.Names and grief
Hyginus lists seven Heliades: Merope, Helie, Aegle, Lampetia, Phoebe, Aetherie, and Dioxippe. Aeschylus's lost Heliades names Phaethousa and Lampetia; a scholiast on the Odyssey gives Phaethusa, Lampetia, and Aegle. Their brother Phaethon lost control of Helios's chariot and fell — usually after Zeus's thunderbolt saved the earth from burning.
The sisters mourned until metamorphosis: they became poplars, and their continuing tears hardened into amber that fell into the Eridanus. Hyginus alternatively says they were changed because they had yoked the chariot for Phaethon without Helios's leave. A proverb in Plutarch links their tears with great wealth.