Esantionul din imagine este cuartul stalactitic. Se observa in mod clar 3 salactite distincte alcatuite din cristale de cuart. Probabil in centrul lor este pirita, imbracata cu cristale de cuart.
This quartz crystals are forming 3 stalactites (over a pyrite core, maybe).
The photos can be used if source is acknowledged.
Cuprul nativ apare ca depozit hidrotermal asociat cu alterarea rocilor eruptive si vulcanice sau in infiltratiile poroase ale rocilor sedimentare. Ocurenta este comuna, insa doar in cantitati foarte mici.
Native copper occurs as a hydrothermal deposit associated with alteration of igneous and volcanic rocks, or infiltrating porous sedimentary rocks. Native copper, though widely distributed, occurs only in small amounts.
Sistemul de cristalizare/ Cristal system: cubic
Habitus: dendritic, ramuros; cristale cubice sau dodecaedrice/ dendritic, branching forms, cubic or rhombododecahedral crystals.
Culoare/ Colour: rosu/ copper-red
Clivaj/ Cleavage: nu/ none
Duritate/ Hardness: 2.5-3
Luciu/ Luster: metalic
Transparenta/ Transparency: opac
Alte proprietati/ Other: ductil, solubil in acid azotic; ductility, readily soluble in nitric acid.
The photos can be used if source is acknowledged.
office of strategic contemplation 