Restricted sense of "precious stone, gem" developed in English from early 14c. Figurative meaning "beloved person, admired woman" is late 14c. Colloquial family jewels "testicles" is from 1920s, but jewel as "testicle" dates to late 15c. Jewel-case is from 1753.
Also in Middle English "a jest, prank, trick" (late 14c.); "a deception, fraud, artifice" (mid-14c.). As a verb, "to furnish with gauds," from late 14c. Related: Gauded; gauding; gaudful; gaudless.
1520s, in jewelery, "the ring or flange in which a jewel or group of jewels is set," from French collet "little collar" (13c.), diminutive of col "neck," from Latin collum "neck" (see collar (n.)). Meaning "a band or collar" is from 1560s.
"a precious stone" (especially when cut or polished), c. 1300, probably from Old French gemme (12c.), from Latin gemma "precious stone, jewel," originally "bud," from Proto-Italic *gebma- "bud, sprout," from PIE *geb-m- "sprout, bud" (source also of Lithuanian žembėti "to germinate, sprout," Old Church Slavonic prozebnoti "to germinate").
The two competing traditional etymologies trace it either to the root *gembh- "tooth, nail" [Watkins] or *gem- "'to press." De Vaan finds the second "semantically unconvincing" and leans toward the first despite the difficult sense connection.
Of persons, "a rare or excellent example (of something)" from late 13c. Alternative forms iemme, gimme persisted into 14c. and might represent a survival of Old English gimm "precious stone, gem, jewel," also "eye," which was borrowed directly from Latin gemma.
"base frame of an automobile," 1903, American English; earlier "sliding frame or carriage-base for a large gun" (1869), "window frame" (1660s), from French châssis "frame," Old French chassiz (13c.) "frame, framework, setting," from chasse "case, box, eye socket, snail's shell, setting (of a jewel)," from Latin capsa "box, case" (see case (n.2)) + French -is, collective suffix for a number of parts taken together. Compare sash (n.2).