Marcasite: Difference between revisions
More actions
Created page with "thumb|right|frame|Marcasite from Wheal Unity, Gwennap * Lustre:Metallic, Sub-Metallic * Transparency:Opaque * Colour:Pale brass-yellow, tin-white on fresh exposures. * Streak:Dark-gray to black. * Hardness:6 - 6½ on Mohs scale * Tenacity:Brittle * Cleavage:Distinct/Good Distinct on {101}. {110} in traces. * Fracture:Conchoidal, Sub-Conchoidal [https://www.mindat.org Data from mindat.org] ===Pages mentioning pyrite=== {{Special:WhatLinksHere/Ma..." |
No edit summary |
||
| Line 1: | Line 1: | ||
[[File:Marcasite.jpg|thumb|right|frame|Marcasite from Wheal Unity, Gwennap]] | [[File:Marcasite.jpg|thumb|right|frame|Marcasite from Wheal Unity, Gwennap]] | ||
[[File:wunity-marcasite.png|thumb|right|frame|Curve trace from this specimen]] | |||
* Lustre:Metallic, Sub-Metallic | * Lustre:Metallic, Sub-Metallic | ||
| Line 12: | Line 13: | ||
[https://www.mindat.org Data from mindat.org] | [https://www.mindat.org Data from mindat.org] | ||
===Pages mentioning | Marcasite is chemically identical to [[pyrite]] but has a different crystal structure and is more silver in colour. It seems quite rare in Cornwall, it's taken me a long time to find any. This could be due to the fact that it's massive form is very similar to arsenopyrite, and I may have overlooked it in the past. This specimen is really nice though, very reflective and large well formed crystals. Marcasite is a mineral that forms 'hopper' crystals, stepped hollow forms similar to salt crystals. | ||
I had a surprise getting a curve trace from it, I was expecting it to behave like pyrite - which is easy enough to find spots with a voltage drop and quite leaky, but functioning asymmetric rectification properties. However it seemed like a very good conductor all over, and only with a lot of patience could I find the curve I captured, with a very slight notch at around -0.5V. This actually seemed like it was present in different spots, so I'm fairly confident it is a property of the crystal. I tried it with silver (which was far too conductive) and steel as a cat's whisker. | |||
===Pages mentioning marcasite=== | |||
{{Special:WhatLinksHere/Marcasite}} | {{Special:WhatLinksHere/Marcasite}} | ||
[[Category: ACE R&D]] | [[Category: ACE R&D]] | ||
Latest revision as of 15:27, 5 August 2026
- Lustre:Metallic, Sub-Metallic
- Transparency:Opaque
- Colour:Pale brass-yellow, tin-white on fresh exposures.
- Streak:Dark-gray to black.
- Hardness:6 - 6½ on Mohs scale
- Tenacity:Brittle
- Cleavage:Distinct/Good Distinct on {101}. {110} in traces.
- Fracture:Conchoidal, Sub-Conchoidal
Marcasite is chemically identical to pyrite but has a different crystal structure and is more silver in colour. It seems quite rare in Cornwall, it's taken me a long time to find any. This could be due to the fact that it's massive form is very similar to arsenopyrite, and I may have overlooked it in the past. This specimen is really nice though, very reflective and large well formed crystals. Marcasite is a mineral that forms 'hopper' crystals, stepped hollow forms similar to salt crystals.
I had a surprise getting a curve trace from it, I was expecting it to behave like pyrite - which is easy enough to find spots with a voltage drop and quite leaky, but functioning asymmetric rectification properties. However it seemed like a very good conductor all over, and only with a lot of patience could I find the curve I captured, with a very slight notch at around -0.5V. This actually seemed like it was present in different spots, so I'm fairly confident it is a property of the crystal. I tried it with silver (which was far too conductive) and steel as a cat's whisker.