A precious stone.
And the foundations of the wall of the city were garnished with all manner of precious stones. The first foundation was jasper; the second, sapphire; the third, a chalcedony; the fourth, an emerald; 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. ( Revelation 21:19-20 )
Bibliography Information"Entry for 'Jacinth'". A King James Dictionary.