in botany. See Hyacinthus.

natural history a genus of pellucid gems, whose colour is red with an admixture of yellow.

The hyacinth, though less striking to the eye than any other red gems, is not without its beauty in the finest specimens. It is found of various sizes, from that of a pin's head to the third of an inch in diameter. Like common crystal, it is sometimes found columnar, and sometimes in a pebble-form; and is always hardest and brightest in the larger masses.

Its colour is a dull or deadish red, with an admixture of yellow in it; and this mixed colour is found in all the variety of tints that a prevalence of the red or of the yellow in different degrees is capable of giving it.

Our jewelers allow all those gems to be hyacinths or jacinths, that are of a due hardness with this mixed colour; and as they are of very different beauty and value in their several degrees and mixture of colours, they divide them into four kinds; three of which they call hyacinths, but the fourth, very improperly, a ruby. 1. When the stone is in its most perfect state, and of a pure and bright flame-colour, neither the red nor the yellow prevailing, in this state they call it hyacintha la belle. 2. When it has an over proportion of the red, and that of a duller colour than the fine high red in the former, and the yellow that appears in a faint degree in it is not a fine, bright, and clear, but a dusky brownish-yellow, then they call it the saffron hyacinth. 3. Such stones as are of a dead whitish-yellow, with a very small proportion of red in them, they call amber-hyacinths. And, 4. When the stone is of a fine deep red, blended with a dusky and very deep yellow, they call it a rubacelle. But though the over-proportion of a strong red in this gem has made people refer it to the class of rubies, its evident mixture of yellow shows that it truly belongs to the hyacinths.

The hyacinth la belle is found both in the East and West Indies. The oriental are the harder, but the American are often equal to them in colour. The rubacelle is found only in the East Indies, and is generally brought over among the rubies, but it is of little value: the other varieties are found in Silesia and Bohemia.