Editorial Feature

Brianyoungite – Occurrence, Properties, and Distribution

Sep 22 2014

Brianyoungite was named after Brian Young (1947– ), a field geologist and mineralogist associated with the British Geological Survey, who provided the first specimens.

Properties of Brianyoungite

The following are the key properties of brianyoungite:

Cell Data

Space group: P2₁/m, P2₁ or P222₁
a = 15.724(3)
b = 6.256(5)
c = 5.427(5)
β = ~90°
Z = 4

Crystal Data

Monoclinic, pseudo-orthorhombic, or or orthorhombic
Point group: 2/m, 2, or 222
Crystals are thin tapering blades elongated along [010], to 2 µm, aggregated in rosettes
X-ray powder pattern: 15.44 (100), 7.88 (100), 2.714 (40), 1.565 (30b), 5.25 (20), 2.577 (20), 2.397 (20)

Chemical Composition

Elements	Content 1	Content 2
ZnO	71.47	73.27
H₂O⁺	10.70	10.81
CO₂	9.90	9.91
SO₃	6.62	6.01
Total	98.69	100.00

Optical Properties

Optical class: Biaxial (+) (probable)
α = 1.635; β = 1.650; γ = n.d.
2V(meas.) = n.d.

Estimated Properties

Electron density	Bulk density (electron density) = 3.86 g/cm³ note: Specific gravity of brianyoungite = 4.01 g/cm³
Photoelectric	PE_{Brianyoungite} = 29.43 barns/electron U=PE_{Brianyoungite} x ρ electron density= 113.69 barns/cm³
Fermion index	Fermion index = 0.02 Boson index = 0.98
Radioactivity	Brianyoungite is not radioactive

How to Identify Brianyoungite

Brianyoungite can be identified in the field by its transparent colorless form, which has perfect cleavage. This mineral has a vitreous-glassy luster with white streak. The density of brianyoungite is 3.93 - 4.09 g/cm³ with a hardness of 2-2.5 - lying between the hardnesses of gypsum and fingernail keratin.

Global Distribution

Brianyoungite is found in the following places:

England - At the Brownley Hill mine, near Alston, and the Smallcleugh mine, Nenthead, Cumbria
Germany - At the Alexander and Bastenberg mines, Ramsbeck, Sauerland; in the Marie mine, Wilnsdorf, Siegerland; at the Friedrichssegen mine, near Bad Ems, and in the Katzental area, near Nothweiler, Rhineland-Palatinate; from the Neue Frohlichkeit mine, near St. Andreasberg, Harz Mountains; from the mines Gelbe Birke, near Schwartzemberg, Langenau, near Brand-Erbisdorf, Fortuna, near Breitenbrunn, and Reiche Zeiche, Freiberg, Saxony; from Wittmansgereuth, near Saalfeld, Thuringia
Belgium - At Altenberg, near Aachen
Australia - Found at Laurium, Greece. From Broken Hill, New South Wales.

Occurrence of Brianyoungite and Useful Mineral Association

Brianyoungite is a rare secondary post-mine mineral which occurs in limestone-hosted oxidized Pb–Zn ores. It is often associated with minerals such as gypsum, goethite, smithsonite, and pyrite.