Fülöppite
 | This article, Fülöppite, has recently been created via the Articles for creation process. Please check to see if the reviewer has accidentally left this template after accepting the draft and take appropriate action as necessary.
Reviewer tools: Inform author |
| Fülöppite | |
|---|---|
 Fülöppite from Baia Mare, Romania | |
| General | |
| Category | sulfosalts |
| Formula (repeating unit) | Pb3Sb8S15 |
| Strunz classification | 2/E.21-50 or 2.HC.10a |
| Dana classification | 03.06.20.01 |
| Crystal system | Monoclinic [1] 2/m, space group C 2/c |
| Identification | |
| Formula mass | 2,076.59 g [2] |
| Color | Lead-gray; may tarnish steel-blue or bronzy white [1] |
| Crystal habit | Short prismatic and pyramidal |
| Fracture | Uneven [1] |
| Tenacity | Brittle |
| Mohs scale hardness | 2½ |
| Luster | Metallic |
| Streak | reddish grey [1] |
| Diaphaneity | Opaque |
| Specific gravity | 5.2 |
| References | [3] [1] |
Fülöppite is a rare member of the Plagionite Group; other group members are heteromorphite Pb7Sb8S19, plagionite Pb5Sb8S17 and semseyite Pb9Sb8S21.[4] It was named in 1929 for Dr Bela Fülöpp, (1863-1938), a Hungarian lawyer, statesman and mineral collector.[3][4]
Structure
Fülöppite forms a homologous series with other members of the plagionite group. The structures of these minerals differ by the thickness of a galena sheet which occurs in all of them. Fülöppite has the thinnest such sheet.[4]
Crystallography
Unit Cell Parameters: Z = 4 a = 13.44 Å, b = 11.73 Å, c = 16.93 Å β = 94.7° [3][4][5] Crystals are short prismatic parallel to [201], up to 3 mm long, or pyramidal. They are striated on {100} parallel to [010] and on {112} parallel to [110]. Forms which have been observed include (001), (100), (101), (112), (111), (223), (111) and (221).[1] Curved crystals are common.[4][5] The numbers in brackets are Miller indices.
Appearance
The crystals are short prismatic and pyramidal, with lead-grey colour that may tarnish to steel-blue or bronzy white.[1] The streak is reddish grey. The crystals are opaque, with a metallic lustre.[6][2]
Optical Properties
Reflected light anisotropism is the property of a material which appears to change colour when viewed under crossed polarised light in a reflected light microscope. Fuloppite exhibits moderate reflected light anisotrophism in blue-green to red-brown.[4][2]
RL Colour (in reflected plane polarised light) Bronzy white (Webmin), white (Mindat).
Reflectivity in air (540 nm): 31.9 – 40.1% (Dana, Webmin), 36.1–42.0% (HOM)
Physical Properties
Fracture: Uneven (AM15, All except Dana) Tenacity Brittle (All except Dana) Hardness 2½ (All) Specific Gravity measured 5.2, calculated 5.2 (All) Fuloppite melts easily in an open tube yielding sulphur fumes and a deposit of Sb2S2. Not attacked by concentrated hydrochloric acid (AM15)
Occurrence
Type Locality: Dealul Crucii Adit (Crucii Hill; Kreuzberg; Kereszthegy), Baia Mare (Nagybánya), Maramureș Co., Romania (Mindat) Type Material: The Natural History Museum, London, England, 1929,248 (HOM).
Occurrence and Associations Of hydrothermal origin (All except Dana).
Association:Zinkenite, semseyite, Fizélyite, andorite, freieslebenite, geocronite, boulangerite,jamesonite, cinnabar, sphalerite, marcasite, quartz, dolomite (HOM). Fülöppite was first reported in Britain from Wet Swine Gill, Caldbeck Fells, Cumbria. It was described as dark grey metallic patches of fibrous crystals accompanying stibnite. More recently, rare dark red resinous to submetallic subhedral to euhedral crystals associated with stibnite were identified as being close to fülöppite. [7]
Name in Other Languages: German: Fülöppit Russian:Фюлеппит Simplified Chinese: 柱硫锑铅矿 Spanish: Fülöppita
References
- ^ a b c d e f g <American Mineralogist (1930): 15: 201-202.abstract from Mineral. Mag. (1929) 22: 179-184>
- ^ a b c d <http://www.webmineral.com/data/Fuloppite.shtml#.VZYMb0am2J8>
- ^ a b c <Gaines et al (1997) Dana’s New Mineralogy, Eighth Edition. Wiley>
- ^ a b c d e f g <http://www.mindat.org/min-1559.html>
- ^ a b c <http://www.handbookofmineralogy.org<>
- ^ Cite error: The named reference
Mindawas invoked but never defined (see the help page). - ^ <JRS>Journal of the Russell Society 8(2) 101-102>