Help identifying.
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Author:  RAGGMAN [ Sat Jun 01, 2019 6:28 pm ]
Post subject:  Help identifying.

I've had this rock for 20ys it was found in Sydney Australia I'm curious what it actually is.

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Author:  arglthesheep [ Mon Jun 03, 2019 1:40 am ]
Post subject:  Re: Help identifying.

looks like quarz to me...

Author:  RAGGMAN [ Mon Jun 03, 2019 5:09 am ]
Post subject:  Re: Help identifying.

Thanks for that it has rainbows and it looks like fossils or something. I should get it checked out professionally.

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Author:  Barbra Voltaire, FGG [ Mon Jun 03, 2019 10:57 am ]
Post subject:  Re: Help identifying.

It is quartz.
No fossils; it contains inclusions of other minerals.
The Quartz Page wrote:
Rainbow or Iris Quartz
There are two types of quartz crystals that are called rainbow or iris quartz.

One is fairly common: Quartz crystals often show cracks running through them, usually caused by mechanical stress, and these sometimes show rainbow-colored reflections. Due to the conchoidal fracture of quartz the cracks are curved and the width of the fissure is not the same over the whole extent, but changes gradually. The cracks are usually very thin, and often just filled with air. Light that passes through the crack will get partially reflected on both walls of the crack. If the width of the crack is of the same order of magnitude as the wavelength of light, both reflected light beams will show interference colors: Parts of the spectrum will be canceled out, and the reflected light appears colorful. The color depends on the width of the crack and the angle at which the light passes the crack. As the width of the crack changes gradually, so does the color and this causes a rainbow-colored reflection. This effect is known as iridescence (hence the name iris quartz) and can also be observed when thin layers of oil swim on water.

Author:  Stephen Challener [ Mon Jun 03, 2019 4:57 pm ]
Post subject:  Re: Help identifying.

Normally you can't identify stones 100% from a photo, but this is one of those rare exceptions. The color and crystal form are extremely distinctive. The only thing it could be other than quartz is an extremely sophisticated fake meant to imitate quartz, which doesn't seem likely.

Author:  RAGGMAN [ Mon Jun 03, 2019 6:49 pm ]
Post subject:  Re: Help identifying.

It's definitely real it was found in deep excavation work on the edge of Sydney Harbour. Thank you so much for your help.

Author:  1bwana1 [ Mon Jun 03, 2019 8:12 pm ]
Post subject:  Re: Help identifying.

Quartz, natural Citrine.

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