I always like to see if I can add more (though Jim is great!)
ivory 1181, Anglo-Fr. ivorie, from O.N.Fr. ivurie (12c.), from L. eboreus "of ivory," from ebur (gen. eboris) "ivory," probably via Phoenician from an African source (cf. Egyptian ab "elephant," Coptic ebu "ivory"). Replaced O.E. elpendban, lit. "elephant bone." Applied in slang to articles made from it, such as dice (1830) and piano keys (1854). As a color, esp. in ref. to human skin, it is attested from 1590. Ivories as slang for "teeth" dates from 1782. Ivory tower (1911) first used 1837 in Fr. (tour d'ivorie) by critic Charles-Augustin Sainte-Beuve (1804-1869) with reference to the poet Alfred de Vigny, whom he accused of excessive aloofness. "Et Vigny, plus secret, Comme en sa tour d'ivoire, avant midi rentrait." [Saine-Beuve, "Pensées d'Août, a M. Villemain," 1837]
crystal O.E. cristal "clear ice, clear mineral," from O.Fr. cristal, from L. crystallum "crystal, ice," from Gk. krystallos, from kryos "frost," from PIE base *kru(s)- "hard, hard outer surface" (see crust). The mineral has been so-called since O.E.; it was regarded by the ancients as a sort of fossilized ice. As a shortened form of crystal-glass it dates from 1594.
And finally ... I bounced around the German-English name and translation sites and the best I could get was that Scwon means "swan" ...I had to throw in a "h" after the "c" ...