Namesake Minerals #1

Every Monday, I will be releasing a post about namesake minerals. I mentioned this term when I wrote a blog for UCL Museums and Collections last year. It describes a mineral that is named after a person, or, by coincidence, resembles someone’s name. So, to start off this series of posts, I thought I would describe two of my namesake minerals.

vanadinite specimens

Vanadinite, from Mibladen, 12km northeast of Midelt, Morocco (author’s image)

Quick facts:

  • Phosphate mineral, part of the apatite group
  • Found in the oxidised zone of lead bearing deposits
  • Type locality: Zimapán, Hidalgo, Mexico
  • Formula: Pb5(VO4)3Cl; part of a chemical series, when vanadium is replaced by phosphorous or arsenic, it forms pyromorphite and mimetite respectively
  • Crystal system: Hexagonal
  • Hardness: 2.5-3
  • Density: 6.88g/cm3

The closest namesake mineral I can find for my first name is vanadinite. I first came across this mineral while cataloguing UCL’s Geology Collections. Luckily, I now have a beautiful specimen of vanadinite in my collection (above picture). Vanadinite was first discovered in 1801 by Andrés Manuel del Río in Zimapán, Hidalgo, Mexico. At the time, it was referred to as ‘brown lead ore’ and del Río claimed that it contained a new element which he named panchromium, and then later erythronium. Unfortunately, other scientists convinced him that this new element was just an impure form of chromium. Decades later in 1830, Nils Gabriel Sefström was studying Swedish iron ores and rediscovered del Río’s element. Sefström named this element vanadium after Vanadis, the Scandinavian goddess of beauty. Years later, the brown lead ore was given the name vanadinite due to its high content of vanadium.

gabrielite

Gabrielite, from Lengenbach Quarry, Binn Valley, Switzerland (image from mindat.com)

Quick facts:

  • Sulphosalt mineral
  • Found in association with other arsenic sulphosalts
  • Type locality: Lengenbach Quarry, Binn Valley, Switzerland
  • Formula: Tl6Ag3Cu6(As,Sb)9S21
  • Crystal system: Triclinic
  • Hardness: 1.5-2
  • Specific gravity: 5.36g/cm3

My other namesake mineral is a much better match and is called gabrielite. This is a sulphosalt mineral and unfortunately, due to its rarity, information on it is scarce. The mineral is named after Walter Gabriel who discovered gabrielite in 2002 in Lengenbach Quarry, Binn Valley, Switzerland. He is a mineral photographer and an expert on Lengenbach minerals. For advanced readers, there’s a paper from 2006 about the crystal structure of gabrielite.

So keep an eye out for these posts. You might find your own namesake mineral!

 

References:
http://www.mindat.org/min-4139.html
http://www.mindat.org/min-26386.html
https://en.wikipedia.org/wiki/Vanadinite

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