Vanadinite

This month we will look at the mineral vanadinite. In the world of mineral micromounts, vanadinite, with its typical red color and distinctive crystal forms, is a favorite among mineral micromounters. I would hazard a guess that just about every mineral micromounter has at least one vanadinite specimen in their collection. Vanadinite is classed as a lead chlorovanadate and is the result of the action of vanadium rich hydrothermal solutions in the oxidation zone of primary lead sulphide deposits. Vandanite is part of a chemical series with the minerals pyromorphite and mimetite and these three minerals are sometimes found in the same mineral deposit. Pyromorphite is a lead chlorophosphate and mimetite is a lead chloroarsenate. All three of these minerals have very similar crystal forms, varying primarly only in color. Although the pure form of each is colorless or very pale yellow, vanadinite is primarily red, pyromorphite is primarily green and mimetite is primarily yellow. Vanadinite crystallizes in the Hexagonal-Tripyrimidal form. The most common crystal habits are:

Vanadinite was first discovered at Zimapan, Hildago, Mexico and is named for its Vanadium content. I have noted that most of the Vanadinite seen at mineral shows in the past year is from the Moroccan mines. Vanadinite specimens from other locations are available from dealers on the internet and via mail order but you really have to "dig" for them. An interesting aspect of vanadinite in micromount form is the reflection of light from inclusions and internal fractures in the crystal. Although this mineral is primarily red in color, light reflected internally comes out as yellow. I have found that some of the vanadinite from the Hamburg Mine, when brightly illuminated looks like it is on fire! Some of the vanadinite from Mibladen, Morocco when brightly illuminated shows a beautiful shiller from many parallel reflective planes in the crystal.