Item#26: Cuart stalactitic/ Stalactitic quartz

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.

Item#2: Native Copper

native-copper.jpgcopper-detail.jpg

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.