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evin likes rocks
Joined: 26 May 2017
Posts: 9
Location: chi
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Posted: May 26, 2017 02:23 Post subject: Vivianite Oxidation |
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Hi everyone,
I would like to know how long it takes the mineral Vivianite to oxidize.
I need to oxidize the entire rocks without damaging the rock chemically (other than the change from oxidization). Physically, the rocks will be crushed to a fine powder to maximize surface area.
I would like to speed up the process if possible, but I only found info on how to oxidize iron faster that included chemicals which I dont know would help oxide Vivianite.
I just bought 4 small (less than 2x2 inch) tumbled unpolished vivianite stones that are blue on the exterior. I can post pics if needed.
This is my first post, so I hope this is in the right topic.
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alfredo
Site Admin
Joined: 30 Jan 2008
Posts: 979
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Posted: May 26, 2017 02:51 Post subject: Re: Vivianite Oxidation |
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If you're planning on powdering the vivianite anyway, you'll find it oxidizes almost immediately on grinding to powder, which is why the color of the powder quickly changes to deep blue and it gets used for making blue pigments.
If you want to be certain that it has all oxidized, you could wet the powder with hydrogen peroxide and let it dry out again.
By the way, are you doing this for the purpose of creating a natural mineral pigment? If so, just be certain that there is absolutely no pyrite associated with your vivianite, because the powdered pyrite is black and will ruin the color. I've met a few people who were visiting mineral shows specifically to hunt for minerals they could grind up for pigments: cinnabar, hematite, limonite, azurite, lapis lazuli and willemite were all popular for the pigment hobbyists. Vivianite is much more expensive than azurite, but makes a more stable blue, as azurite tends to slowly alter into malachite and gets greenish.
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evin likes rocks
Joined: 26 May 2017
Posts: 9
Location: chi
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Posted: May 26, 2017 10:57 Post subject: Re: Vivianite Oxidation |
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Thank you, Alfredo,
Yes, I am doing this to make a pigment! Surprised but glad to hear that these people are at least somewhat common, so that the topic of mineral pigments is one i can get at least some information on.
If the pyrite turns vivianite black, how can i seperate it from the vivianite?
i think one of my vivianite pieces has a bit of pyrite in the middle due to its darkness and the slight luster around it.
Pics included.
Mineral: | Vivianite |
Dimensions: | under 5*5cm |
Description: |
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6104 Time(s) |
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Mineral: | Vivianite |
Dimensions: | under 5*5cm |
Description: |
same rocks as other photo |
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Viewed: |
6086 Time(s) |
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