Lexical Definition

‎ἀμέθυστος‎ améthystos (am-eth'-oos-tos) amethyst G:N-F
from ‎Α‎ (as a negative particle) and a derivative of ‎μεθύω‎

amethyst.

Usage: 3 forms in 4 verses
Form Translated As     In Verse(s)
ἀμέθυστοσ amethyst Rev.21.20
αμέθυστοσ amethyst LXX.Exod.28.19LXX.Exod.39.12
αμέθυστον amethyst LXX.Ezek.28.13

Abbott-Smith

ἀμέθυστος, -ου, ἡ (acc. to Plut., < ἀ- μεθύω, being regarded as an antidote against drunkenness), [in LXX: Ex 28:19 36:19* 39:12* Ez 28:13*;]
amethyst, a purple quartz: Re 21:20.†

Abbott-Smith References

Book Refs
Exodus 28:19 · 36:19* · 39:12*
Ezekiel 28:13
Revelation 21:20

Liddell-Scott-Jones

ἀμέθυστος, ον,

(μεθύω) not drunken, without drunkenness, [Refs 1st c.AD+]: comparative, [Refs]

__II not intoxicating, perhaps so used in [Refs 4th c.AD+]substantive, ἀμέθυστον, τό, remedy against drunkenness, [Refs 1st c.AD+]; also ἀμέθυστος, , [Refs 1st c.AD+] —hence, such things as were supposed to act as remedies, i.e. ,
__II.1 kind of herb, [Refs 1st c.AD+]; ={σέλινον ἄγριον}, Ps.-[Refs 1st c.AD+]
__II.2 amethyst, [LXX+NT+5th c.BC+]:—also ἀμέθυστον, τό, [Refs 3rd c.BC+]
__II.3 ἀμέθυστον, τό, kind of grape, Colum.3.2.24.

LSJ Scripture Refs: LXX.Exod.28.19Rev.21.20