Outlines of mineralogy

Chapter 22: PLATINUM, OR PLATINA.

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About This Book

A concise scientific treatise that organizes fossil and inorganic substances by their constituent chemical components, advocating composition-based genera and species rather than superficial traits. It defines mineralogy, explains a natural system founded on prevalent parts and variations in mixture, and critiques reliance on color, hardness, and texture because these features often vary independently of composition. The work describes analytical approaches and difficult cases, offers supplemental genera in appendices, and supplies practical aids such as tables and an index to assist identification and application of mineral substances.

PLATINUM,
OR
PLATINA.

§ 151.

Its ſpecific gravity is 18,000 ^[60], when very pure. It diſſolves in aqua regia, and the loſs of phlogiſton during the ſolution, according to the experiments hitherto made may be expreſſed by 756. Beſides the muriatic acid, which when dephlogiſticated diſſolves every metal, no acid acts upon platina without it has undergone a previous calcination. It ſeems to retain its phlogiſton more obſtinately than any other metal. To melt it requires a heat greater than that at which iron melts.

§ 152.

PLATINA native united to iron. Native.

Cronstedt Min. § 179.

I believe it has never been found quite free from iron, but this can be ſeparated by art ^[61].