Please ID - Chromite? Chromiumite?

Hi

These were found again in Kemi, Finland. Kemi apparently has a Chromium plant/mine area which is outside of Kemi, these were found near the harbour.

Are the crystals Chromite? Why is the rock purple? Streak was blackish.

Also, when white light shines onto it, the purple becomes very strong purple colour. Why is that?

Many thanks

Claire

Hi Claire,

I think you're correct about the little black octahedral crystals being Chromite. This looks very much like Chromite ore. I think that the purple colored mineralization may be Chromian Clinochlore like this: [www.mindat.org] Good luck with it.

Ron

Claire, Check whether the colour looks different under tungsten filament (incandescent) light bulb, and under fluorescent tube lights. That's sometimes interesting for purple minerals coloured by chromium.

looks like chromite with chromian clinochlore (form. kammererite)

Also keep in mind that much (if not most) "Chromite" is actually not Chromite stricto sensu (i.e. Fe-dominant) but rather the Mg-dominant analogue Magnesiochromite. It is safer to label "Chromite-Magnesiochromite series".

Lefteris.

Many thanks for the information :)

I have doen a bit of 'digging' - [en.gtk.fi]

Hope you can get into this site - interesting :) The rock is Chromitite

Hello Claire
Magnesiochromite has not been found at Kemi. It is chromite (Hytönen, K. Suomen Mineraalit 1999). Chromitite is an error,
it should be chromite ore.

Ilkka

"Chromitite" is a petrological term / rock name.
"Chromite ore" is a technical / mining term.
Franz Bernhard

Another reason to get our dictionary of mining, mineral and related terms running.

Rock Currier
Crystals not pistols.