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GeneralPenberthy Croft mine Update

2nd Dec 2015 19:38 UTCJohn Betterton

Please can this updated information be added to its webpage.

Penberthy Croft mine is situated approximately one mile from the village of Goldsithney in the parish of St. Hilary, Cornwall, England. NGR, SW 555 324. The locality is a prolific source of rare and unusual secondary minerals of which the Cu-Pb-Fe-Al arsenates are the best known. Penberthy Croft is the type locality for the following species: the copper lead arsenate bayldonite and the aluminium arsenates bettertonite and penberthycroftite.

Penberthy Croft is the first, or joint first recorded site for the tin hydroxide minerals jeanbandyite and natanite in the British Isles. Segnitite is also first recorded at this location.

Note on the mineral lists:

Reference to adamite at Penberthy Croft is from Kingsbury. Given the doubts about the provenance of other Kingsbury specimens (Ryback et al. 1998, 2001), investigated this and discredited the occurrence.

Should be followed by a separate list of discredited/fraudulent/unconfirmed minerals from the main list of only confirmed species:

List of confirmed mineral species supported by analytical data:

Adamite

Agardite-(Ce)

Agardite-(La)

Alloclasite

Anatase

Anglesite

Ankerite

Annabergite

Aragonite

Arsenolite

Arsenopyrite

Aurichalcite

Azurite

Bayldonite (TL)

Beaverite-(Cu)

Bettertonite (TL)

Beudantite

Birnessite

Bismuthinite

Bismutite

Bornite

Brochantite

Bulachite

Calcite

Caledonite

Carminite

Cassiterite

Cerussite

Chalcoalumite

Chalcophyllite

Chalcopyrite

Chrysocolla

Clinochlore

Connellite

Copper

Corkite

Cornubite

Cornwallite

Covellite

Cuprite

Cyanotrichite

Devilline

Dolomite

Duftite

Erythrite

Fluorapatite

Galena

Goethite

Gypsum

Halite

Halloysite

Hidalgoite

Jarosite

Jeanbandyite

Langite

Laurionite

Leadhillite

Libethenite

Linarite

Liskeardite

Malachite

Mansfieldite

Mattheddleite

Millerite

Mimetite

Mixite

Monazite-(La)

Natanite

Olivenite

Orthoclase

Parnauite

Penberthycroftite (TL)

Pharmacosiderite

Philipsburgite

Phosgenite

'Pitticite'

Plumbogummite

Pseudomalachite

Pyrite

Pyromorphite

Quartz

Redgillite

Scheelite

Schulenbergite

Scorodite

Segnitite

Siderite

Silver

Smithsonite

Sphalerite

Stannite

Stilpnomelane

Sulphur

Tenorite

'Varlamoffite'

Woodwardite

Wroewolfeite

Wulfenite

Zincolivenite

99 mineral species are valid for this location not 113 as currently stated on the Mindat.org website. List of discredited/fraudulent/unconfirmed/to be confirmed species. (K= Kingsbury Collection at the NHM either discredited or fraudulent). Others to be confirmed due to lack of analytical data:

Arseniosiderite K

Atacamite K

Beraunite discredited

Bieberite discredited

Cattiite K

Ceruleite discredited

Churchite-(Y)

'Hornblende' discredited

Lepidocrocite

Mottramite discredited

Paratacamite K

Plumbojarosite K

Rosasite K

Serpierite discredited

Tyrolite discredited

Vanadinite discredited

Wurtzite

Zálesíite discredited

Unknowns (UK PC = Unknown Penberthy Croft) from the John Betterton Collection:

UK PC2 ? MnxOx

UK PC3 ? Cu+Zn+As+Mn+Fe+Co??+La???+O

Additional work is required on these unknowns.

I have other minerals to be added when published in the mineralogical literature. By John Betterton (Museum Geologist/Mineralogist). December 2015.

19th Nov 2016 13:01 UTCJohn Betterton

Massage for Mindat Managers:

Please could you change the formula of bettertonite on the Mindat website to conform with the latest version from the IMA listings, i.e. change to: [Al6(AsO4)3(OH)9(H2O)5]·11H2O

Under comment for penberthycroftite on the Mindat website please remove “crusts have dull and nearly waxy lustre”.

Add to the mineral listing from this locality:

Dundasite (structural and chemical data was used for identification a paper will be published on this occurrence in time).

John Betterton (Museum Geologist)

19th Nov 2016 13:09 UTCDavid Von Bargen Manager

Is this published anywhere or are these your personal observations?

19th Nov 2016 15:17 UTCJason Evans

I hope the Mindat managers enjoy their massage.

19th Nov 2016 17:33 UTCJohn Betterton

Dear Sir,

The dundasite identification is verrified by Powder X-ray diffraction (PXRD) and by wavelength dispersive spectrometry. The paper for this occurrence will be published when other more complex associated mineral species has been identified.

Hope to see the above added shortly.

John Betterton (Museum Geologist)

21st Nov 2016 19:11 UTCJohn Betterton

Short update to Penberthy croft mine

The comments section for penberthycroftite was a copy and paste error. Please ignore it.

Please add for bettertonite:

Name: Honors John Betterton (b. 1959, London), a museum geologist/mineralogist at Haslemere Educational Museum, Surrey, England, for his extensive contributions to the characterisation of minerals from the Penberthy Croft mine for more than 30 years. Also is an advanced mineral collector and micromounter.

Why has dundasite not yet been added to the species yet? It is a confirmed species!

Thank you.

John Betterton (Museum Geologist)

25th Nov 2016 20:57 UTCRalph S Bottrill 🌟 Manager

Done thanks John.

Do you have a photo of Bettertonite we can add? And one of yourself too?

6th Jan 2017 14:13 UTCJohn Betterton

Dear Sirs,

I wonder is it possible to add the chemical classifications ie both Dana and Strunz for bettertonite and penberthycroftite.

Many thanks folks,

John Betterton

6th Jan 2017 14:25 UTCDavid Von Bargen Manager

The problem is I don't know who, if anyone, is keeping up these classifications. The man who was keeping an eye on the Strunz classification passed away a few years ago.

7th Jan 2017 17:43 UTCJohn Betterton

Dear Sir,

Sorry to hear this can anyone else please add this important data? Also I see that the formula for bettertonite is missing some waters ie: It should be:

[Al6(AsO4)3(OH)9(H2O)5]·11H2O with attention to lower case characters.

I have general photographs of the new mineral and will try to sort out soon. As for photos of my self I do not wish any photographs to appear online due to personel and cyber security reasons, sorry.

Best regards,

John Betterton

7th Jan 2017 18:15 UTCUwe Kolitsch Manager

> Also I see that the formula for bettertonite is missing some waters

We cannot change this at the moment - a bug.

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