Chrome Diopside

  • Author: ChemViews & Chemie in Unserer Zeit
  • Published Date: 22 May 2014
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
thumbnail image: Chrome Diopside

Related Articles

Diopside has the composition CaMgSi2O6 and forms monoclinic prismatic crystals of the space group C2/c, but they are somewhat rare. More often granular and globular structures are found.

The name comes from the Greek dis for twice and opsis for face and refers to the fact that the crystals are often twinned. J. B. d'Andrada first described the mineral in 1800. It was then called Coccolit. Diopside is classified as belonging to the subgroup of chain and band silicates with 2-periodic single chains Si2O6/pyroxene. Diopside is a rock-forming mineral that occurs worldwide in alkaline and ultraalkaline rocks, and has also been detected in lunar rocks.

In chrome diopside, a small proportion (up to 2 %) of the Mg2+ ions in the octahedral sites are replaced by Cr3+ ions. The CrO6 chromophores are responsible for the emerald color of the mineral. As the chromium ions have a higher charge than the magnesium ions, an accompanying exchange of either calcium with sodium or silicon with aluminum is necessary to balance the charge.
Chrome diopside is commonly found in olivine and often found close to diamond deposits in South Africa. Also, high-pressure mixed crystals that contain 40 % NaCrSi2O6 have been found in the diamond mines of Yakutia.

Diopside and chrome diopside have no great economic impact other than their use as stones in jewelry.

The chrome diopside pictured above was foundin Outokumpo, Finland.
Picture © Ekkehard Diemann, University of Bielefeld, Germany,

Chrome Diopside is the answer to Guess the Mineral (1).

The next mineral quiz was published in early June.
The lucky winners are I. Abramova, USA, and C. Escudero, Spain.

Article Views: 5652

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from, please contact us first for permission. more

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH