sardonyx (Greek #4557)

Revelation
21:20  The fifth
ho (Greek #3588)
the definite article; the (sometimes to be supplied, at others omitted, in English idiom)
KJV usage: the, this, that, one, he, she, it, etc.
Pronounce: ho
Origin: ἡ (hay), and the neuter τό (to) in all their inflections
pemptos (Greek #3991)
fifth
KJV usage: fifth.
Pronounce: pemp'-tos
Origin: from 4002
, sardonyx
sardonux (Greek #4557)
a "sardonyx", i.e. the gem so called
KJV usage: sardonyx.
Pronounce: sar-don'-oox
Origin: from the base of 4556 and ὄνυξ (the nail of a finger; hence the "onyx" stone)
; the sixth
hektos (Greek #1623)
sixth
KJV usage: sixth.
Pronounce: hek'-tos
Origin: ordinal from 1803
, sardius
sardios (Greek #4556)
sardian (3037 being implied), i.e. (as noun) the gem so called
KJV usage: sardius.
Pronounce: sar'-dee-os
Origin: properly, an adjective from an uncertain base
; the seventh
hebdomos (Greek #1442)
seventh
KJV usage: seventh.
Pronounce: heb'-dom-os
Origin: ordinal from 2033
, chrysolite
chrusolithos (Greek #5555)
gold-stone, i.e. a yellow gem ("chrysolite")
KJV usage: chrysolite.
Pronounce: khroo-sol'-ee-thos
Origin: from 5557 and 3037
; the eighth
ogdoos (Greek #3590)
the eighth
KJV usage: eighth.
Pronounce: og'-do-os
Origin: from 3638
, beryl
berullos (Greek #969)
a "beryl"
KJV usage: beryl.
Pronounce: bay'-rool-los
Origin: of uncertain derivation
; the ninth
ennatos (Greek #1766)
ninth
KJV usage: ninth.
Pronounce: en'-nat-os
Origin: ordinal from 1767
, a topaz
topazion (Greek #5116)
a gem, probably the chrysolite
KJV usage: topaz.
Pronounce: top-ad'-zee-on
Origin: neuter of a presumed derivative (alternately) of τόπαζος (a "topaz"; of uncertain origin)
; the tenth
dekatos (Greek #1182)
tenth
KJV usage: tenth.
Pronounce: dek'-at-os
Origin: ordinal from 1176
, a chrysoprasus
chrusoprasos (Greek #5556)
a greenish-yellow gem ("chrysoprase")
KJV usage: chrysoprase.
Pronounce: khroo-sop'-ras-os
Origin: from 5557 and πράσον (a leek)
; the eleventh
hendekatos (Greek #1734)
eleventh
KJV usage: eleventh.
Pronounce: hen-dek'-at-os
Origin: ordinal from 1733
, a jacinth
huakinthos (Greek #5192)
the "hyacinth" or "jacinth", i.e. some gem of a deep blue color, probably the zirkon
KJV usage: jacinth.
Pronounce: hoo-ak'-in-thos
Origin: of uncertain derivation
; the twelfth
dodekatos (Greek #1428)
twelfth
KJV usage: twelfth.
Pronounce: do-dek'-at-os
Origin: from 1427
, an amethyst
amethustos (Greek #271)
the "amethyst" (supposed to prevent intoxication)
KJV usage: amethyst.
Pronounce: am-eth'-oos-tos
Origin: from 1 (as a negative particle) and a derivative of 3184
.