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 Post subject: Rutilated Amethyst
PostPosted: Wed Nov 11, 2020 11:42 pm 
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I don't know why I was surprised to see this in the amethyst. Rutile is common enough in quartz. I had just never seen it before. This stone comes from SRI LANKA. There are also lots of little rectangular crystals but I don't know what they are. Anyone?
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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 4:16 am 
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It is strange, but rutile in amethyst is unusual to the point of being unheard of. Even though the form would be unusual, I'd guess those are needles of yellow goethite rather than rutile--the way they radiate from a single point, plus the association with the spheres of hematite (along with goethite being a classic in amethyst) point in that direction. Still, even if I'm right it's an unusually excellent example.

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 Post subject: Re: Rutilated Amethyst?
PostPosted: Thu Nov 12, 2020 9:32 am 
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Thanks!
Any idea why amethyst is not a host to rutile?

I guess I'll have another look at some of the "rutilated" stones I have to see if I mislabelled them.


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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 1:42 pm 
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I imagine it is a function of available elements.
Amethyst owes its color to iron color centers.


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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 3:32 pm 
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Several years back I slabbed a Quartz point section and found the following through out the pieces. This pic was taken just with a low end macro camera, I can only imagine what it would like in an image with one of your scopes.
Any Ideas on these needles?

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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 4:10 pm 
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Hematite I would giess, classic "beetle leg" formation.

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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 6:46 pm 
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Beetle legs LOL, I was told once the reddish needles were Goethite.

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 Post subject: Re: Rutilated Amethyst
PostPosted: Thu Nov 12, 2020 8:05 pm 
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Goethite is typically yellow, vs hematite which is red.

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