jacinth

A rare red, orange, or yellow gemstone variety of the mineral zircon.

Jacinth is a red transparent variety of zircon used as a gemstone.

Alfred, Lord Tennyson used the word 'jacinth' in his epic Morte D'Arthur, describing the jewelled hilt of Excalibur:

"There drew he forth the brand Excalibur,
And o'er him, drawing it, the winter moon,
Brightening the skirts of a long cloud, ran forth
And sparkled keen with frost against the hilt:
For all the haft twinkled with diamond sparks,
Myriads of topaz-lights, and jacinth work
Of subtlest jewellery."