Leeches are usually olive green to brown in colour, darker patches and spots being scattered over a paler ground.
They are minute worms with coloured oil drops (green, olive green or orange) contained in the epidermis.
Ferrous oxide produces an olive green or a pale blue according to the glass with which it is mixed.
As a picturesque tree, for park and ornamental plantation, it is among the best of the conifers, its colour and form contrasting yet harmonizing with the olive green and rounded outline of oaks and beeches, or with the red trunk and glaucous foliage of the pine.
The olive green syenite found on Mount Ascutney, near the Connecticut river, in Windsor county, is a hornblendeaugite.
It is thus obtained as an olive green precipitate which is insoluble in acids and alkalis.