Je vous emmène à travers mes vidéos découvrir mon expérience acquise depuis plus de 30 ans a silloner le globe entier à la recherche de pierres précieuses, de rencontre mémorables mais aussi de difficulté parfois …
This is a quartz, more exactly a transluscent chalcedony (itself a variety of cryptocrystalline quartz) which shows concentric bands sometimes containing opale. Comes in many colors, banded, forming concentric bands, more or less circular up to oval. Their formation is so far discuted : or
Found in 1821 by P.Ström and named “acmite” from the Greek “point, edge” in reference to the typical pointed crystals. But in 1835 Berzelius named it aegirine after Aegir, the Teutonic god of the sea. Richer in sodium than augite, it oxydizes itself, pruducing chlorite,
Described in 1886 by Charles Friedel who named it after the French mineralogist Gilbert Joseph Adam who found this mineral. Its color depends on the metallic ions present : cuproadamite colored by copper is green, manganoadamite colored by manganese is pink-purple such as cobaltoadamite and
Actinolite belongs to the amphibole group, discovered in 1794 by the mineralogist Kirwan. The name actinolite is derived from the Greek “aktis”, meaning “beam” or “ray” and “lithos”, meaning “stone”; referring to the mineral’s radiating fibrous nature. The name “actinolite” was given by René Just
