Galena

Galena could be the ore that is major of and silver.  It is usually well crystallized and forms in several interesting and distinct crystal shapes. Some cuboidal crystals have their edges cut by the partial octahedral growth, some octahedral crystals have their points planar by cuboidal growth, and plenty of crystals are found somewhat intermediate cuboidal and octahedral. It is really a very metal that is common mineral found in many localities worldwide. Galena, additionally known as lead look, is that the natural mineral variety of lead(II) sulphide. it’s the foremost vital ore of lead and a vital supply of silver. A mineral is one among the foremost galore and cosmopolitan sulphide minerals. Galena is typically found as bright, metallic, cube-shaped crystals. Most of the lead minerals, comparable to mineral and Anglesite area unit secondary minerals shaped from mineral. Impurities within the structure of the mineral, comparable to silver and metal, might amendment Galena’s cleavage properties. The mineral containing metal might exhibit octahedral cleavage, and silver in mineral might cause a specimen to exhibit flaky, slightly bent cleavage fragments.

Category: Sulfide mineral, octahedral subgroup
Chemical Formula: PbS
Crystallography: Isometric – Hexoctahedral
Crystal Habit: Most commonly cubic, crystals to a meter on an edge are known; more rarely cubo-octahedral or octahedral. May be tabular on [001]; also forms reticulated masses and skeletal crystals. As cleavable masses, coarse to very fine granular; fibrous, plumose.
Twinning: Twin plane [111], as both contact and penetration twins; twin plane [114], lamellar.

 

Cleavage: [001] Perfect; Parting on [111]
Fracture: Sub-Conchoidal to Uneven; fracture rarely seen because of the perfect cleavage
Tenacity: Brittle
Hardness (Mohs): 2.5 – 2.75
Density: 7.2 – 7.6 (g/cm3)
Luminescence: None
Radioactivity: Not Radioactive
Health Warning: CAUTION: Contains Lead – always wash hands after handling. Avoid inhaling dust when handling or breaking. Do not lick or ingest.

 

Color: Light to dark Lead Gray, Silver Gray; sometimes with a bluish tint
Transparency: Opaque
Luster: Metallic, Dull
Refractive Index: None; Opaque
Birefringence: None; Opaque
Dispersion: n/a
Pleochroism: n/a