in 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 gem, 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. They are harder than quartz-crystals; transparent, and formed into prisms pointed at both ends. These points are always regular with regard to the number of facets; being four on each facet, but the latter seldom: the sides of the main body are also very uncertain, in regard both to their number and shape; being found of four, five, six, seven, and sometimes of eight sides; sometimes being so compressed as almost to resemble the face of a spherical faceted garnet. Sometimes they are of a dodecaedral form like the garnet, but with more obtuse angles. The specific gravity of the hyacinth, according to Dutans, is 2.631; but Rome de Lisle says that Brifon found it to be 3.6873; and the European hyacinths to be 3.760.

The hyacinth, as well as all other gems, is divided into oriental and occidental; the former being very hard and brilliant, so that they are frequently ranked among the topazes; but when soft, they are supposed to belong to the garnet kind, as mentioned under that article. The hyacinths, however, may generally be distinguished from the garnets by losing their colour in the fire, becoming white, and not melting. There is a kind of a yellow-brown hyacinth, resembling the colour of honey, which is distinguished from the rest by the remarkable property of not being electrical, and being likewise inferior in hardness.

Our jewellers allow all those gems to be hyacinths or jacinths that are of a due hardness with the mixed colour above mentioned; 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 dusky 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-hyacinth. And, 4. When the stone is of a fine deep red, blended with a dusky and very deep yellow, they call it a rubacee. But though the over proportion of a strong red in Hyacinthia, this gem has made people refer it to the clas of rubies, its evident mixture of yellow shows that it truly belongs to the hyacinth.

The hyacinth la belle is found both in the East and West Indies. The oriental is the harder, but the American is often equal to it 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 Silexia and Bohemia.

HYACINTHUS, HYACINTH, in botany: A genus of the monogynia order, belonging to the hexandria clas of plants; and in the natural method ranking under the 10th order, Coronariae. The corolla is campanulated, and there are three millerose pores at the top of the germen. There are six species; of which the most remarkable is the orientalis, or eastern hyacinth. Of this there are a great number of varieties, amounting to some hundreds, each of which differs from the rest in some respect or other. This plant hath a large, purplish, bulbous root, sending up several narrow erect leaves eight or ten inches long; the flower-stalk is upright, robust, and succulent, from 10 to 15 inches in height; adorned upward with many large funnel or bell-shaped flowers, swelling at the base, and cut half way into six parts; collected into a large pyramidal spike of different colours in the varieties; flowering in April or May.

These plants are cultivated with the greatest success in Holland, from whence great numbers are annually imported into Britain. Each variety is by the florists distinguished either by the name of the place where first raised, or the person who raised them, or the names of illustrious personages, as of kings, generals, poets, and celebrated ancient historians, gods, goddesses, &c. They are sold by all the seed-dealers. The prices are from three pence per root to five or ten pounds or more; and some varieties are in such high esteem among the florists, that 20l. or 30l. will be given for a single bulb. They are hardy, and will prosper anywhere, though the fine kinds require a little shelter during the winter. They may be propagated either by seeds or offsets from the roots.

The properties of a good oriental hyacinth are, a stem perfectly upright, of moderate length, and so strong and well-proportioned that it will sustain the weight of the florets without bending: the florets should be large, swelling below, expanded above, and numerous, 10 or 15 at least, but are often 20 or 30 in number; and should be placed equally round the stem, the pedicles on which they grow longer below than above, diminishing gradually in length upward in such a manner as to represent a pyramid, and each pedicle sufficiently strong to support the florets without drooping. The curious in these plants are careful never to plant the fine sorts two years together in the same bed of earth; for, by planting them every year in a fresh bed, the beauty of the flowers is greatly improved.