PLUMBOGUMMITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated phosphates
    Crystal system : Trigonal
    Chemistry : PbAl3(PO4)2(OH)5 H2O
    Rarity : Uncommon

Plumbogummite is an hydrated phosphate from the oxidation zone of lead deposits, found in association with other secondary lead minerals and sometimes in replacement of pyromorphite or barite (pseudomorph). Its name comes from the Latin plumbum (lead) and gummi (gum) in allusion to its chemical composition and its appearance. Plumbogummite occurs in botryoidal, stalactitic and spherolitic masses with a concentric or fibroradiated texture, rarely in prismatic crystals with a hexagonal shape. Its color is extremely variable : gray-white, yellowish gray to reddish brown, sometimes green or blue.

Main photo : Plumbogummite from Yangshuo Mine, Guangxi, China © Rob Lavinsky

Plumbogummite pseudomorph after pyromorphite from Yangshuo Mine, Guangxi, China
Plumbogummite from Clara Mine, Germany © Michael Förch
Plumbogummite from Penberthy Croft Mine, St Hilary, Cornwall, UK © Steve Rust
Plumbogummite on pyromorphite from La Fumade, Tarn, France © François Garric

Plumbogummite in the World

The most beautiful specimens of plumbogummite are magnificent pale blue-green barrels, sometimes more than 5 cm from the Yangshuo Mine (Guangxi, China) which are in reality pyromorphite pseudomorphs. This discovery dating from 2014 redefined the top for the species and highlighted this mineral that was previously little known to collectors. Plumbogummite is also particularly abundant in the polymetallic veins of English Cornwall and Cumbria (Great Britain). It is also known in Broken Hill (Australia) and in several American deposits. Resistant to alteration, it is part of the diamondiferous alluvium of Diamantina (Minas Gerais, Brazil).

Plumbogummite in France

In France, the most beautiful specimens of plumbogummite are stalactitic and mounded masses which come from the Poullaba mine near Huelgoat (Finistère); they constituted the best specimens in the world before the discovery of Chinese plumbogummites. It is also reported at La Fumade (Tarn), at Kaymar (Aveyron), at Echassières (Allier) which produced pretty transparent sub-millimeter pseudo-octahedra and centimeter-scale pyromorphite pseudomorphs, etc...

Twinning

No twins known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 4 to 5
Density : 4.01
Fracture : Irregular to sub-conchoidal
Streak : White

TP : Translucent
RI : 1.653 to 1.704
Birefringence : 0.022
Optical character : Uniaxial +
Pleochroism : Low
Fluorescence : Rarely bluish

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/