Source edition
Theophrastus, Theophrasti Eresii Opera quae supersunt omnia, Volume 3, Wimmer, Teubner, 1862
Source data
Open Greek and Latin · CC BY-SA 4.0
Cloned and adapted by Humanitext, with ongoing edits.
Summary
This treatise is a scientific and philosophical work that systematically investigates the origins, classifications, and physical and chemical properties of stones, earths, and minerals found in nature. The author begins by tracing the material components of these substances to "water" and "earth," classifying them based on the principles of solidification. The first half details the various reactions of stones to heat—such as melting, bursting, and flammability—along with the unique properties of precious stones used for seals (such as smaragdus and lygurion) and rare materials like pearls and coral. The latter half transitions to practical minerals like touchstones for testing gold, the classification of natural earths and pigments, and the manufacture of synthetic pigments (such as white lead and cinnabar) through human art. Finally, by discussing the properties of gypsum used in construction and bonding, the work demonstrates how natural substances are integrated into practical human life and decorative arts.