Mellite. Mellitate of Argilla

Mellite at first sight resembles Amber and has been confounded with it, but Amber is not found crystallized, and this substance is mostly found crystallized in octaëdrons, sometimes truncated as in our specimen, and is said to be found in cubes and in rhomboidal dodecaëdrons. The facets are mostly smooth. It is softer than Amber, with a more waxy appearance. It refracts double, has a trifling electricity by rubbing. In burning it emits no odour, whereas Amber generally gives a rather powerful and agreeable odour, although there are some instances of the contrary. It varies in colour from light to dark yellow. It is found on vegetable remains more or loss approaching to wood coal. It was first noticed in Thuringia, and since with mineral pitch in Switzerland, &c. With the blowpipe it whitens and does not emit any flame (according to some authors it emits a weak flame) and is reduced to ashes. The primitive crystal is an obtuse octaëdron, composed of two four-sided pyramids, forming at their junction an angle of 93°22′ the incidence of the planes of these pyramids upon each other is 118°4′—Haüy.

Spec. Grav. 1.666 to 1.5858.