Actinolite

The Count de Bournon baying lately published the differences between certain minerals hitherto confounded together as varieties of Actinolite, some of which really belong to Hornblende, to which Haüy has united all the varieties of Actinolite and Tremolite, we are glad through his kindness of an opportunity of exhibiting a Scotch specimen of that sort to which he has retained the name Actinote. It is in Serpentine, and is quite new to me; it is rendered beautiful by a particular chatoyant lustre that depends upon interior faces or fibres reflecting a yellowish light, under peculiar circumstances, varying according to the stronger or weaker adhesion or greater or less transparency of the surface and the polish of the next plate or fibre. There are two directions of the laminæ, so that the light is reflected in two principal directions. The nucleus of Actinolite, according to Bournon, is a rhomboidal prism of about 130° and 50°, the terminal planes of which are inclined towards the acute edges at about 94°.

The dark green crystals added to this figure for illustration are from Norway, where they were found intermixed with prismatic Hornblende. They show the position of the terminal face, which is the distinguishing character.