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Apuanite

Posted by Rock Currier  
avatar Apuanite
May 23, 2009 05:17AM
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Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?



Apuanite
Fe2+Fe3+4Sb3+4O12S Tetragonal
Italy
Tuscany, Lucca Province, Apuan Alps, Stazzema, Ponte Stazzemese, Buca della Vena Mine

Apuanite xl 2.57mm wide© D. Preite - M.C.

Auuanite xl .92mm© Chinellato Matteo
1.4mm Apuanite xl.© D.Preite

~4mm Apuanite crystal in calcite© Marco Barsanti
~8mm Apuanite crystal© Marco Barsanti

Apuanite and Versiliaite are thus far found only at The Buca della Vena Mine, in Italy. Both were described in the American Mineralogist in 1979 1 as minerals related to Schafarzikite2. Apuanite is tetragonal and Versiliaite is orthorhombic but it is difficult if not impossible to identify them by "eyes only" and analysis is required. In the x-ray patterns of these two minerals, the distinction between them can easily be made because of the split peaks of the orthorhombic Versiliaite. Of the two, Versiliaite is much rarer. Both show an important relationship chemically and crystlaographically with Schafarzikite which is also associated with them in the Buca della Vena mine. Apuanite is most often found as massive aggregates of black metallic color interlayered with metamorphic dolomitic limestone. Locally this is sometimes called "grezzoni". Tabular prismatic crystals of Apuanite, though not common but can reach 5 cm in size.2, Probably the best and bigger specimens of apuanite were found near the end of the mines life (1985-1987). Most commonly apuanite crystals don't exceed 10 mm. Most of them are included in the dolomitic metamorphic limestone (really a variety of dolomitic marble) near or at the the contact with phillitic metamorphic rocks.3 Sometimes Apuanite crystals show (expecially the ones found from in the area of the mine known as "castello" winking smiley, have a red coating of of cinnabar (see photo # 1). Most recently in other tunnels and stopes the of the Buca della Vena mine, Apuanite has been found in calcite veins. These are found lower and more easterly in respect to the "castello" room occurrence. Some material has also been found in the southern part of the mine. See photo #2.
1.Versiliaite and apuanite: derivative structures related to schafarzikite. Mellini M. and Merlino S. American Mineralogist(1979), 64, 1235–1242".
2. Minerali della Provincia di Lucca. Associazione Micro-Mineralogica Italiana, Cremona, (Biagioni, C. - 2009 ).
3. Versiliaite and apuanite, two new minerals from the Apuane Alps, Italy. Am. Min., 64: pp 1230-1234). (Mellini M., Merlino S., Orlandi P., 1979
[Marco Barsanti 2010]

Found so far only in this iron mine “as massive black aggregates in veinlets within thin layers of dolomite, which are relics of the metasomatic process. Associated with the black minerals in the veinlets is spathic barite. Crystals of apuanite are black with metallic luster, platy on (001) and with perfect (110) cleavage. A well developed crystal is characterized by the forms {001}, {110}, {112} and {114}”1 These forms yield blocky rectangular looking crystals. “The mineral occurs disseminated as aggregates of crude microcrystals filling fractures in cavities in dolomite. Some of these aggregates exceed 5 cm in diameter. A few very rare crystals have been found to exceed 1 cm in size.”2 Very few if any of these have reached the markets in the United States. What would a good crystal of this mineral cost you if available? Perhaps less than $500 if you were lucky.
1 American Mineralogist, Vol. 64 p1230+. - 2 Mineralogical Record, Vol.17, 1986, p264.


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Picture selection on 12/26/12

Rock Currier
Crystals not pistols.



Edited 12 time(s). Last edit at 12/26/2012 07:35PM by Rock Currier.
avatar Re: Apuanite
June 24, 2010 08:38PM
Marco, What you have contributes is very good. I have worked your text over and you should read what I have written and make sure it expresses exactly what you want to say. I have never x-rayed Apuanite or its associated minerals and you should make sure what I wrote is OK. The photos you referred to did not come through in your post. If you will just give me the photo numbers, Ill see that those get incorporated into the article. Also I think the term "grezzoni"winking smiley does not translate well and I don't know what you mean by it. If you can explain it better to me, I am sure I can make a better translation. Also can you give me some idea of how much material was collected in the mine? How many flats of material that had Apuanite? How many tabular crystals in excess of say 2 cm were there? Are there 10 specimens of Apuanite to Versiliaite". Can you describe the best specimen of Apuanite you ever saw? Did you collect it? All of these thing I think would be of interest to collectors and researchers and dealers. A little more work, and I think we will have a pretty good article. Thanks.

Rock Currier
Crystals not pistols.
avatar Re: Apuanite
June 24, 2010 10:58PM
    
avatar Re: Apuanite
June 25, 2010 06:11AM
    
Hi Rock:

I have corrected something in the text above. I think that "winking smiley" is just an unwanted effect of a combination of marks.

@David: thank you, now links are active

The term "grezzoni" is a local geological attribute to a triassic metamorphic dolomitic limestone, (pratically it can be considered a kind of marble too), which appears at the bed of the marble formation of Apuan Alps.

For the rest of your questions, i'm collecting data, but in this period my free time is really very short for job reasons which keep me far from my beloved minerals. Probably on half of july i'll start breathing again and i'll post here the other contributions



Edited 1 time(s). Last edit at 06/25/2010 06:15AM by Marco Barsanti.
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