MINERALS INDEX

Actinolite

Albite

Allactite

Allanite

Amphibole Group

Andradite

Anglesite

Anhydrite

Anorthite

Apatite

ApatiteGroup

Apophyllite

Aragonite

Arsenates

Arsenides

Arseniosiderite

Arsenopyrite

Aurichalcite

Axinite

Azurite

Barite

Barylite

Barysilite

Bementite

Biotite

Borates

Bornite

Boroarsenates

Bustamite

Cahnite

Calamine

Calcite

Calcium larsenite

Carbonates

Celestite

Cerusite

Chalcocite

Chalcophanite

Chalcopyrite

Chloanthite

Chlorite

Chlorophoenicite

Chondrodite

Chysolite Group

Clinohedrite

Copper

Corundum

Corundum Group

Crocidolite

Cummingtonite

Cuprite

Cuspidine

Cyprine

Datolite

Desaulesite

Descloizite

Diopside

Dolomite

Edenite

Epidote

EpidoteGroup

FeldsparGroup

Ferroaxinite

Ferroschallerite

Fluoborite

Fluorite

Franklinite

Friedelite

Friedelite Group

Gageite

Gahnite

Galena

Ganophyllite

Garnet

Glaucochroite

Goethite

Graphite

Greenockite

Gypsum

Halloysite

Haloids

Hancockite

Hardystonite

Hastingsite

Hedyphane

Hematite

Hetaerolite

Heulandite

Hodgkinsonite

Holdenite

Humite Group

Hyalophane

Hydrohetaerolite

Hydrozincite

Ilmenite

Jeffersonite

Kentrolite

Larsenite

Lead

Leucaugite

Leucophoenicite

Limonite

Lollingite

Loseyite

Magnesium- chlorophoenicite

Magnetite

Malachite

Manganbrucite

Manganite

Manganosite

Marcasite

Margarosanite

Mcgovernite

Mica Group

Microcline

Millerite

Molybdenite

Mooreite

Muscovite

Nasonite

Native Elements

Neotocite

Niccolite

Norbergite

Oxides

Pargasite

Pectolite

Phlogopite

Phosphates, Arsenates and Vanadates

Prehnite

Psilomelane

Pyrite

Pyrochroite

Pyroxene Group

Pyrrhotite

Quartz

Rhodochrosite

Rhodonite

Roeblingite

Roepperite

Rutile

Scapolite

Schallerite

Schefferite

Serpentine

Serpentine Group

Siderite

Silicates

Silver

Smithsonite

Sphalerite

Spinel

Spinel Group

Stilbite

Sulphates

Sulphides and Arsenides

Sussexite

Svabite

Talc

Tennantite

Tephroite

Thomsonite

Thorite

Titanite

Tourmaline

Tremolite and Actinolite

Unconfirmed Species

Vanadates

Vesuvianite

Willemite

Xonotlite

Zeolites

Zinc schefferite

Zincite

Zircon

Zoisite

 

Lollingite

FeAs2
Orthorhombic

Forms
c(001), a(100), b(010), m(110), e(101), l(011), z(012), and s(111)

Combinations on crystals of lollingite
Forms Localities Illustrations
1 m, e, z Buckwheat mine Figure 14
2 m, e, l Trotter shaft Figure 15
3 c, b, m, e, l, z, s Franklin Figure 16

Crystals of lollingite measured by Berman (247) bore the forms of combination 3, shown in Figure 16.

Figure 16
Crystal of lollingite showing the forms c(001), b(010), m(110), c(101), l(011), z(012), and s(111). Trotter shaft. A, Plan; B, clinographic projection.
fig16.gif (8793 bytes)

The crystals were of unusually fine quality for this mineral, and the axial ratio–a : b : c = 0.5438 : 1 : 1.130–derived from their measurement, is thought to be better than any previously computed.

Composition
A chemical analysis of the Franklin lollingite was made by Bauer, using 0.4 g of carefully selected crystals, with the following result:

Analysis of lollingite
(L. H. Bauer (247), analyst)
Percent Molecular ratio
As

69.80

0.933* 1.78
S

0.21

0.007*  
Fe

29.40

0.530 1

99.41

[*Figures reflected in the value 1.78 shown at right]

The slight deficiency of the analysis is due to the presence of a small and undetermined amount of calcite. Sulphur is practically negligible. There is insufficient arsenic, as shown by the molecular ratio, to give quite the 2 to 1 ratio of lollingite. Such a deficiency is common in analyses of this mineral and has usually been accounted for by assuming the presence of more or less of the leucopyrite molecule, Fe3As4. In this analysis computation indicates the assumed presence of 14 percent of leucopyrite. The specific gravity is 7.505 (Buerger).

Occurrence
Lollingite was found at Franklin in the Buckwheat mine, where granular masses intermingled with franklinite were somewhat rare. It was also recorded, in brilliant tin-white crystals (see Figure 14), by Brush (100), accompanying the unique cubical gahnite that he described.

Figure 14
Pseudo-dodecahedral crystal of lollingite showing the prism m(100), the macrodome e(101), and the brachydome z(012). Buckwheat mine.
fig14.gif (5409 bytes)

At the Trotter shaft tin-white crystals, too rough for measurement, were found sparsely with gahnite in the limestone wall rock. The specimens described by Bauer and Berman (247) were found in 1926 in a drift on the 750-foot level, north. The crystals are sparsely embedded in white limestone of medium grain, together with crystals of gray pyroxene and scattered dots of franklinite. The lollingite crystals are complete individuals, of a brilliant tin-white color, and range in size from tiny specks to crystals with a diameter of an eighth of an inch. They break freely and cleanly from the matrix, and the brilliance of their luster marked them at once as suitable for crystallographic study. They are shown in Figures 15 and 16.

fig15.gif (5311 bytes) Figure 15
Crystal of lollingite of dodecahedral habit, showing the forms m(110), e(101), and l(011). Trotter shaft.

 
Website © by Herb Yeates 1997-2001.
 
 
This page created: January 12, 2001 6:30 PM