Earth as a goddess, from Greek Gaia, spouse of Uranus, mother of the Titans, personification of gaia "earth" (as opposed to heaven), "land" (as opposed to sea), "a land, country, soil;" it is a collateral form of gē (Dorian ga) "earth," which is of unknown origin and perhaps from a pre-Indo-European language of Greece. The Roman equivalent goddess of the earth was Tellus (see tellurian), sometimes used in English poetically or rhetorically for "Earth personified" or "the Earth as a planet."
"fine, soft, loose earth," Old English molde "earth, sand, dust, soil; land, country, world," from Proto-Germanic *mulda (source also of Old Frisian molde "earth, soil," Old Norse mold "earth," Middle Dutch moude, Dutch moude, Old High German molta "dust, earth," Gothic mulda "dust"), from PIE root *mele- "to crush, grind." Specifically, since late (Christian) Old English, "the earth of the grave." Also, from c. 1300 as "earth as the substance out of which God made man; the 'dust' to which human flesh returns."
The proper spelling is mold, like gold (which is exactly parallel phonetically); but mould has long been in use, and is still commonly preferred in Great Britain. [Century Dictionary, 1897]