Download Henry Chen 11B Mineral Presentation

Chemical Formula:
PbS
Chinese Definition:
硫化铅，方铅矿
1. Shape: It is like a cube, and physically, it is
composed of some smaller cubic minerals.
2. Color: Most of Galena minerals are lead
gray, others may be black and silvery.
3. Luster: Galena minerals have large
intensity of reflected light. (It is bright and
metallic!)
Composition:
Pure Galena: 87% --Lead 13% --Sulfur
Impure Galena: 87% --Lead 11.5% --Sulfur
1% --Silver 0.5% --other substances
•Lead is a toxic metal!
Hardness: 2.5-2.75
(we can scratch it with 1 coin!)
Cleavage: In 3 directions
Magnetism: non-magnetic
(Lead is non-magnetic)
Streak: Lead Gray
Effervescence: Galena can only react
with hot, dense Hydrochloric Acid (HCL).
Galena is a main source of industrial lead which has a
wide use in many aspects such as ship’s envelope,
weapons, and cables.
Galena is also a semiconductor which is found use in
early wireless communication systems.
It was used as the crystal in crystal radio sets.
But now, it is replaced by some more suitable
semiconductor devices.
*Interestingly, in Ancient Egypt, one of the oldest uses
of Galena was as kohl, which was applied around the
eyes to reduce the glare of the desert sun.
http://baike.baidu.com/view/82390.htm?from_id=113
20260&type=syn&fromtitle=galena&fr=aladdin
http://en.wikipedia.org/wiki/Galena
Earth Science 11 “Identifying Minerals” Handout