Galena: Difference between revisions
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[[File:Galena-ale-cakes.png|right|frame|A curve trace of galena from Ale & Cakes Mine, Gwennap. Note that the polarity is inverted.]] | |||
* Lustre:Metallic, Sub-Metallic, Dull | * Lustre:Metallic, Sub-Metallic, Dull | ||
* Transparency:Opaque | * Transparency:Opaque | ||
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The "OG" semiconducting mineral from the [[Semiconductor history|early days of radio]], galena was chosen as it was the best material for converting radio frequencies into audible signals, by removing the lower half of the modulation. Often combined with silver cat's whisker contacts. Silver bearing (argentiferous) galena was said to be the best form. | The "OG" semiconducting mineral from the [[Semiconductor history|early days of radio]], galena was chosen as it was the best material for converting radio frequencies into audible signals, by removing the lower half of the modulation. Often combined with silver cat's whisker contacts. Silver bearing (argentiferous) galena was said to be the best form. | ||
Has a higher overall resistance than the [[pyrite|pyrites]] and seems to gradually lose it's properties as it becomes tarnished. | Has a higher overall resistance than the [[pyrite|pyrites]] and seems to gradually lose it's properties as it becomes tarnished. Different point contacts on the same specimen seem to provide reversed junctions, as in the plot above. This is much less common with other minerals. | ||
Revision as of 19:40, 27 June 2026
- Lustre:Metallic, Sub-Metallic, Dull
- Transparency:Opaque
- Colour:Lead-grey
- Streak:Lead-grey
- Hardness:2½ on Mohs scale
- Tenacity:Brittle
- Cleavage:Perfect {001}
- Parting:{111}
- Fracture:Sub-Conchoidal
The "OG" semiconducting mineral from the early days of radio, galena was chosen as it was the best material for converting radio frequencies into audible signals, by removing the lower half of the modulation. Often combined with silver cat's whisker contacts. Silver bearing (argentiferous) galena was said to be the best form.
Has a higher overall resistance than the pyrites and seems to gradually lose it's properties as it becomes tarnished. Different point contacts on the same specimen seem to provide reversed junctions, as in the plot above. This is much less common with other minerals.