Strong’s Greek
G5192 — huakinthos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ὑάκινθος
huakinthos — pronounced hoo-ak'-in-thos
of uncertain derivation; the "hyacinth" or "jacinth", i.e. some gem of a deep blue color, probably the zirkon:-- jacinth.
1 occurrence in the KJV.
Revelation 21:20
The fifth, sardonyx; the sixth, sardius; the seventh, chrysolyte; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.