HAÜY abbé René-Just Traité des caractères physiques des pierres précieuses pour servir à leur détermination lorsqu’elles ont été taillées.

DSB VI.178-183 – Sotheran, Ier supp. 4766; Wheatland 111 ; Sinkankas, I, 2811.

First edition.

In this work, Haüy sets out a method for identifying gemstones even when they have been faceted, that is to say, when their natural crystalline form is no longer directly visible. To do so, he draws on the physical and crystallographic properties of minerals.
He considers that each mineral species possesses not only a geometric structure but also specific properties.

He classifies the gemstones in a table, where they are divided by colour; Haüy then details their reaction to light, specific gravity, hardness, refraction, and their response to electricity and a magnet.

“A work of fundamental importance in the science of gemology and marking the transition from a purely descriptive method to accurate determination of properties and applying them to identification” (Sinkankas).

The three plates by Cloquet depict stones and instruments, notably Nicholson’s hydrometer.

Foxing

Provenance: François Chrétien (bookplate)