WHEWELLITE

    Class : Organic Compounds
    Subclass : -
    Crystal system : Monoclinic
    Chemistry : CaC2O4 H2O
    Rarity : Uncommon

Whewellite belongs to the mineralogical class of organic compounds. Despite this particularity, it is a mineral that is found in various geological contexts : coal deposits, septaria of marls, and even low-temperature hydrothermal veins. It was named in honor of the philosopher and scientist William Whewell, Professor at the University of Cambridge. Whewellite forms flattened crystals with triangular outlines, almost always twinned in the shape of a heart, easy to confuse at first glance with calcite. Whewellite is colorless to milky white, yellowish, rarely brownish. With a hardness of 2.5, it can be scratched with a fingernail. It is a common component of human urinary stones.

Main photo : 4 cm twinned whewellite from Recsk Mine, Hungary © Bela Feher

Whewellite from Zwickau District, Saxony, Germany © Eugene & Sharon Cisneros
Whewellite from Paitzdorf, Germany © Dan Weinrich
Whewellite from Kladno District, Czech Republic © Christophe Boutry
Whewellite from Condorcet, Drôme, France © Jean-Luc Portes

Weloganite in the World

The largest known specimens are 8 cm crystals hosted with honey barite and calcite in septaria from South Dakota, Ohio, and Montana, and crystals beautifully twinned, set in fractures cutting the Kladno coal seams in the Czech Republic. The Burgk coal mine near Dresden (Germany) also yielded good crystals. The hydrothermal veins of Cavnic (Romania) are classic for their centimeter-sized crystals of whewellite.

Weloganite in France

In France, whewellite is found in the septaria of Condorcet (Drôme), in slightly corroded 1 cm crystals, in the geodes of the hydrothermal veins of St-Sylverstre near Urbèis (Haut-Rhin) in very beautiful groups of centimeter-sized crystals, and in white cleavable masses in the uranium veins of Bois-Noirs (Loire).

Twinning

Twinning with {1-01} as contact plane is very common, with or without re-entrant angles, giving heart or prismatic shapes, and pseudo-orthorhombic appearance.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 2.5 to 3
Density : 2.21 to 2.23
Fracture : Conchoidal
Streak : White

TP : Translucent to transparent
RI : 1.489 to 1.650
Birefringence : 0.160
Optical character : Biaxial +
Pleochroism : None
Fluorescence : None

Solubility : Acids

Magnetism : NoneRadioactivity : None

ReCaptcha

This service is used to secure web forms of our website and required if you want to contact us. By accepting it you agree to Google's privacy policy: https://policies.google.com/privacy

Google Analytics

Google Analytics is a service used on our website that tracks, reports traffic and measures how users interact with our website content in order for us to improve it and provide better services.

Facebook

Our website allows you to like or share its content on Facebook social network. By activating and using it you agree to Facebook's privacy policy: https://www.facebook.com/policy/cookies/

YouTube

Integrated videos provided by YouTube are used on our website. By accepting to watch them you agree to Google's privacy policy: https://policies.google.com/privacy

Twitter

Integrated tweets and share services of Twitter are used on our website. By accepting and using these you agree to Twitter's privacy policy: https://help.twitter.com/en/rules-and-policies/twitter-cookies

PInterest

Our website allows you to share its content on PInterest social network. By activating and using it you agree to PInterest's privacy policy: https://policy.pinterest.com/en/privacy-policy/