Meanwhile, at the beginning of the 19th century, the number of cobalt ochres looked much more impressive.

[2]: 503–506  Brown or yellow-brown cobalt-ochres varied in composition, sometimes being a mixture of black and yellow cobalt ochres.

[2]: 510–515 At the same time, Jameson believed that cobalt ochres have a lot in common and can be classified as a special class of minerals.

″The Black, Brown and Yellow Cobalt Ochres, and other similar minerals, ought to be arranged together, and form a particular order by themselves.

[4]: 197  However, from a chemical point of view, Jameson and his contemporaries reduced the entire diversity of cobalt ochres to two groups of chemical compounds of cobalt: oxides (asbolane) and arsenates (erythrite) in different morphological forms of crystallization and with a different set of impurities.