Lewis & Short

sapphīrus, sapphir, sappir, i (i short, Ven. Carm. 6, 2), f., = σάπφειρος, a sapphire, Plin. 37, 9, 39, § 120; Vulg. Apoc. 21, 19; id. Isa. 54, 11.
Form sappir, Plin. 37, 9, 38, § 119.
Form sapphir, Tert. adv. Marc. 2, 10; Vulg. Exod. 28, 18; Hier. in Isa. 15, 54, v. 11 (as m., Isid. 16, 9, 2).