It's hard to tell without optical properties. The upper and lower
photos look like "iddingsite" alteration of olivine and the middle
photo looks like oxyhornblende.
Mike
>
> ----- Original Message -----
> From: Gerrit de Kock
>
> Sent: Friday, November 02, 2007 2:58 PM
> Subject: mineral id
>
> I have the gabbros from the Eburnean from Ghana(~2120Ma old). They are
> not tectonized but suffered severe hydration and then low
> grade metamorphism producing epidote and sphene. In places cpx and
> plagioclase are still preserved as well as an orange mineral. Anyone
> with an idea of what the orange mineral can be. It is unlikely to be
> primary olivine.
>
> Gerrit de Kock
> Council for Geoscience
> South Africa
> [log in to unmask]
> ----- Original Message -----
>
> Disclaimer Legal Notice:
> By having opened and read this electronic mail, you are deemed to have
> understood and accepted all disclaimers and conditions pertaining to
> electronic mail emanating from, and received by The Council for
> Geoscience, further detail of which may be viewed by clicking here:
> Disclaimer
> <gd4209 mmanta pxn subophytic plag cpx texture.alt olivine pyrite
> late.JPG><ga1099 mmanta pxn cpx plag ol alt pyrite.JPG><ga1099
> mmantapxn cpx plag subophytic rutile, ol pyrite idiomorphic xnic.JPG>
|