Short answers, pulled from the story.
Freyja is a Norse goddess associated with love, beauty, fertility, sex, war, gold, and seiðr, the magic for seeing and influencing the future. She is a member of the Vanir, the daughter of Njörðr and the twin sister of Freyr, and her name means lady or mistress in Old Norse.
Freyja rules over love, beauty, fertility, sex, war, gold, and seiðr. She rules the heavenly field Fólkvangr, where she receives half of those who die in battle, while the other half go to Odin's hall, Valhalla.
Freyja owns the necklace Brísingamen, rides a chariot pulled by two cats, and is accompanied by the boar Hildisvíni. She also possesses a cloak of falcon feathers that lets her shift into the shape of a falcon.
Freyja weeps tears of red gold because her husband, the god Óðr, is frequently absent on long travels, and she searches for him under assumed names. Because of this, skalds used kennings such as Freyja's tears and Freyja's weepings to refer to gold.
In Sörla þáttr, Freyja obtained the golden necklace from four dwarfs who were smithying it, agreeing to spend a night with each of them as the price. The story is a euhemerized account found in an extended version of the Óláfs saga Tryggvasonar in the Flateyjarbók manuscript.
Vanadium is named after Vanadís, one of Freyja's names meaning the dís of the Vanir. The element was named for her because of its many beautiful colored compounds.
Yes, reverence for Freyja persisted into the modern period and melded into Scandinavian folklore. In Iceland she was invoked through magical staves as late as the 18th century, and as late as the 19th century rural Swedes still recorded her role as a fertility goddess, including a man in 1880 saying Freyja watched to see if the rye was ripe.