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Approximately 200 gram full slice. Iron IVA
Corey writes:
Sometimes we use acid to make a very thin passivation membrane on the surface to protect from rust. The basic principle is to use an acid like nitric or sulfuric in very high concentration (>70%). I've devised a special way of passivation that made this Gibeon slice show many colors from different angles on the surface - blue, gold, pink, brown.
More about passivation here
See me on Ebay
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Bill Mikuska
3/29/2021 2:13:22 PM |
The colors produced are thin film interference colors produced when the oxidizing acid, in this case nitric acid, forms thin oxide layers of the metals in the meteorite. The color observed depends on the oxide layers thickness.
Passivation can be demonstrated with metallic chromium. A freshly cleaned chromium is solubilized by dilute sulfuric acid, the same does not hold true if the fresh chromium surface is first immersed in nitric acid. Al and Be also illustrate this.
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