Guess the Mineral (5)

Guess the Mineral (5)

Author: ChemViews & Chemie in Unserer Zeit

2014 is the International Year of Crystallography (IYCr). We have taken this opportunity to design a quiz, together with the journal Chemie in Unserer Zeit (ChiuZ). The idea is that you guess the name of a mineral with the help of an image and some tips.

This is the last part of the quiz series. Everyone who gives the correct answer before the required date will be put into a draw to win a book published by Wiley-VCH. For each question there will be two lucky book winners. In addition, at the end of the year we will draw one winner from among all the correct answers to receive an iPad.
So contribute, it’s worth it!

We thank Ekkehard Diemann, University of Bielefeld, Germany, who has made this quiz possible by providing the beautiful images and the texts accompanying these quiz sections.
For tips on how to take such pictures by yourself, read his article on Digital Photography in Chemistry.



5th Mineral

Our mineral (pictured above) has a cubic crystal structure with the space group P43n. The structure is characterized by cage-like frameworks, which in turn are packed to give a cubic structure. The framework can contain additional ions next to the cations in the enclosed cavities.

A close relative of our mineral contains radical anions of sulfur in its cage structure which are regarded as the cause of the intense blue color of the mineral. Various reasons have been suggested for the origin of the color of our mineral: suggestions include the formation of colloidal sodium in the cages and the presence of radical anions such as SO3, Cl2, or O.

The mineral we are looking for is used as a gemstone or for the manufacture of ornamental objects. Tiles and claddings are also made from it.

What is the name of our mineral?

Send your solution indicating your address before January 20, 2015 to [email protected]

→ The answer to this quiz has been published.

More on the International Year of Crystallography (IYCr 2014)

Previous Minerals:


This was the last Guess the Mineral quiz.

The lucky winners of Guess the Mineral (5) are I. Abramova, USA, and C. Weinberger, Germany.
The winner of the iPad is S. Vranckx, Belgium.


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