Dictionary of Medieval Names
from European Sources

Ruby f. Middle English rubie from Old French rubi(s), rubïe 'ruby'.

Withycombe s.n. Ruby is incorrect when she calls it a modern coinage.

England
Early Modern English
1581 Ruby DEmar-vol2 p. 6
Cite as: S.L. Uckelman. "Ruby". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2017, no. 1. http://dmnes.org/2017/1/name/Ruby.