A large precious stone of a red or fiery colour: in early use of unsettled identity, as a ruby, garnet, spinel, etc.; (also) a mythical gem said to…

The jacinth or hyacinth (precious stone).

Any red or fiery gem, such as a ruby or carbuncle. In later use poetic. Now rare.

Either of two stones described by Pliny: (a) a red gem, perhaps a garnet or spinel; (b) a black stone, perhaps a kind of slate.

In modern use, a reddish-orange gem, a variety of zircon; also applied to varieties of topaz and garnet. (= hyacinth, n. 1.)

(Also vermilion-stone.) A particular gem or precious stone. Cf. vermeil, n. 3. Obsolete.

A dark red colour. Also: a precious stone of this colour, esp. a ruby.