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|System:||Monoclinic||Colour:||Green, apple-green, ...|
|Lustre:||Resinous, Waxy, Greasy||Hardness:||4½|
|Name:||Named in 1865 by Arthur Herbert Church in honor of English physician John Bayldon [1837(8) - April 6, 1872 Melbourne, Australia]. Bayldon received degrees from University of Edinburgh and University of London. In the late 1850's, Bayldon was lecturer of botany at the Royal College of Surgeons at Edinburgh. While in Edinburgh, he also published observations of geological and botanical subjects. He emigrated to Australia in 1866 for health reasons. He became surgeon and medical officer of the Melbourne Benevolent Asylum, and, for a short time before his death from Bright's Disease, was the Superintendent of the Ararat Lunatic Asylum. It is widely stated that John Bayldon found the original specimens. He did not. Church (1865) specifically states that the specimen came from a mineral dealer Mr. [Richard] Talling, who had supplied Church with a number of new species.|
A relatively rare secondary mineral occurring in the oxidized zones of polymetallic deposits.
Classification of Bayldonite
|IMA status:||Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"|
|Strunz 8th edition ID:||7/B.33-10|
|Nickel-Strunz 10th (pending) edition ID:||8.BH.45|
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
H : With medium-sized and large cations, (OH,etc.):RO4 = 1:1
|Dana 8th edition ID:||220.127.116.11|
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
5 : (AB)2(XO4)Zq
|Hey's CIM Ref.:||20.5.4|
20 : Arsenates (also arsenates with phosphate, but without other anions)
5 : Arsenates of Ti and Pb
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Type Occurrence of Bayldonite
|Type Locality:||Penberthy Croft Mine, St Hilary, Mount's Bay District, Cornwall, England, UK|
|General Appearance of Type Material:||Grass-green to blackish green mammillary masses.|
|Place of Conservation of Type Material:||It is commonly reported the type specimen is BM 1921,433 at the Natural History Museum, London, England, UK. This is however incorrect - the specimen that has the strongest links with the analyses of A.Church is BM 1964,R8217 also at the NHM, London|
|Year of Discovery:||1865|
|Associated Minerals at type locality:|
Occurrences of Bayldonite
|Geological Setting:||Oxidized zones of copper- and lead-bearing deposits.|
Physical Properties of Bayldonite
|Lustre:||Resinous, Waxy, Greasy|
|Diaphaneity (Transparency):||Transparent, Translucent|
|Colour:||Green, apple-green, yellow-green; dark green to black (crystals)|
|Streak:||Siskin green to apple green|
|Fracture:||Irregular/Uneven, Conchoidal, Sub-Conchoidal, Fibrous|
|Density (measured):||5.24 - 5.65 g/cm3|
|Density (calculated):||5.707 g/cm3|
Crystallography of Bayldonite
|Class (H-M):||2/m - Prismatic|
|Space Group Setting:||C2/c|
|Cell Parameters:||a = 14.081Å, b = 5.892Å, c = 10.147Å|
β = 106.5°
|Ratio:||a:b:c = 2.39 : 1 : 1.722|
|Unit Cell Volume:||V 807.18 Å³ (Calculated from Unit Cell)|
|Morphology:||Crystals rare. Common as mammillary crusts with a fibrous structure; fine-grained massive; pulverulent.|
|Twinning:||Pseudoscalenohedral trillings with the composition plane (311).|
|X-Ray Powder Diffraction:|
Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
|X-Ray Powder Diffraction:|
Optical Data of Bayldonite
|RI values:||nα = 1.951 nβ = 1.970 nγ = 1.991|
|Maximum Birefringence:||δ = 0.040|
Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
|Surface Relief:||Very High|
|Dispersion:||r < v strong|
|Optical Extinction:||Y^elongation = 45°; X=b|
Chemical Properties of Bayldonite
|Simplified for copy/paste:||PbCu3(AsO4)2(OH)2|
|Essential elements:||As, Cu, H, O, Pb|
|All elements listed in formula:||As, Cu, H, O, Pb|
Relationship of Bayldonite to other Species
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
Other Names for Bayldonite
|Fluorescence in UV light:||Not fluorescent in UV.|
|Other Information:||Soluble in HCl with difficulty.|
|Health Warning:||No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.|
References for Bayldonite
Church (1865) Journal of the Chemical Society, London: 18: 265.
Lacroix, A. (1910) Minéralogie de la France et des ses colonies, Paris. 5 volumes: vol. 4: 513.
Biehl (1919) Inaugural Dissertation Münster (as Parabayldonite, Cuproplumbite).
Biehl (1921) Min. Abstracts: 1: 202 (as Parabayldonite, Cuproplumbite).
Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679: 45.
Biehl (1925) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 62: 341 (as Parabayldonite, Cuproplumbite).
Cesbron, F. and H. Vachey (1974) The unit cell and twin of bayldonite. Mineralogical Magazine, 39, 716–718.
Ghose, S. and C. Wan (1979) Structural chemistry of copper and zinc minerals. VI. Bayldonite, (Cu, Zn)3Pb(AsO4)2(OH)2: a complex layer structure. Acta Crystallographica: B35: 819–823.
Sumín de Portilla, V., M. Portillo Quevedo and V.I. Stepanov (1981) The structure of bayldonite: chemical analysis, differential thermal analysis, and IR spectroscopy. American Mineralogist, 66, 148–153.
Internet Links for Bayldonite
|Specimens:||The following Bayldonite specimens are currently listed for sale on minfind.com.|
Localities for Bayldonite
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
(TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
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