Chromate of Iron, or chomiferous Oxide of Iron Enlarge
July 1 1813 published by Jas Sowerby London.
Exotic Mineralogy
LX
Ferrum chromiferum

Chromate of Iron, or chomiferous Oxide of Iron

  • Syn.
    • Chromate de Fér. Bulletin des Sciences, &c.
    • Fer chromaté. Haüy, IV. 129.
    • Eisen-chrom. Karsten.

About fifteen years ago Chromate of Iron was discovered by M. Pontier near Gassin, in the department of the Var, in France. It has since been found in Siberia and America. Not long after its discovery, the Chromic Acid was prepared from it, and combined with Lead to form a fine yellow or reddish yellow pigment, which was sold in Paris, and has proved to be a very valuable addition to the pallet of the artist.

The Chromate of Iron is usually disseminated through masses of Chlorite or Talc; in the American the Talc is often coloured of a delicate pink, probably from a slight admixture of Chrome Oxide with it. Fracture conchoidal, slightly laminated, with rather a dull surface; colour brownish black, with less metallic lustre than Magnetic Oxide of Iron; it is soft and rather brittle. The smaller specimen is a remarkably rich piece, it was lent me by Thomas Meade, Esq., a zealous and scientific collector of the fossils of the West of England; he received it from near Baltimore in America. The other is also an American specimen. The worthy President of the Royal Academy, having been assisted by American friends, has had preparations of it made by Mr. Edmund Davy, late of the Royal Institution, which he has found well adapted to his art, and used successfully. I herein beg to thank him for his kind answer to my enquiries upon the subject.

Analysis of the French variety, by Vauquelin.
Chromic Acid 43.0
Iron Oxide 34.7
Alumine 20.3
Silex 2.0
100.0
Of the Siberian, by Laugier.
Chrome Oxide 53
Iron Oxide 34
Alumine 11
Silex 1
99
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