May 14 2014
Galena is the primary ore mineral of lead. Its discovery dates back to 3000 BC, and its name is derived from the Latin word galena, meaning dross from melted lead.
Properties of Galena
The key physical properties of Galena are as below:
- Cell Data
- Space group: Fm3m
- a = 5.936
- Z = 4
- Crystal Data
- Cubic
- Point group: 4/m 3 2/m
- Crystals: most commonly cubic, crystals to a meter on edge are known; more rarely cubo-octahedral. May be tabular on {001}; also form 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
- X-ray powder pattern: Synthetic 2.969 (100), 3.429 (84), 2.099 (57), 1.790 (35), 1.327 (17), 1.714 (16), 1.484 (10)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
Content 3 |
| Pb |
85.50 |
85.9 |
86.60 |
| Cu |
0.07 |
Trace |
- |
| Sb |
- |
0.7 |
- |
| Bi |
- |
0.2 |
- |
| S |
13.31 |
12.6 |
13.40 |
- Optical Properties
- Opaque
- Lustre – Metallic
- Color- lead-grey, white in polished section
- Estimated Properties
| Electron density |
Bulk density (electron density) = 6.23 g/cm3
note: Specific gravity of Galena = 7.60 g/cm3 |
| Photoelectric |
PEGalena = 1623.65 barns/electron
U = PEGalena x ρelectron density = 10108.40 barns/cm3 |
| Fermion index |
Fermion index = 0.19
Boson index = 0.81 |
Radioactivity
|
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Galena is not radioactive
|
How to Identify Galena
The color of galena is lead-grey, but it appears white in polished sections. It is brittle by nature. Its hardness varies from 2.5 to 2.75. It exhibits a metallic lustre.
Global Distribution
Galena is widely distributed in the following locations:
- USA – from Coueur d’ Alene district, Idaho; Shoshone Co. Colarado; Mississippi Region; Tri-state District, Missouri
- Czech Republic – from Pribram
- Germany – from Saxony, Hesse; Clausthal in Harz Mountains
- France – from Pontigibaud
- England – from Alston Moor, Cumbria
- Scotland – from Wanlockhead, Dumfries
- Mexico – from Santa Eulalia
- Ireland – Mogul Mine, Tipperary
Occurrence of Galena and Useful Mineral Association
Galena occurs in a number of environments, such as hydrothermal veins (formed under various temperatures), metamorphic deposits, and in pegmatites. Limestones and dolostones are common in host rocks.
Some of the minerals with which galena is associated are spharelite, marcasite, pyrite, chalcopyrite, siderite, silver minerals, dolomite, quartz, and many other hydrothermal minerals.
References