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Petalite eg. how to find minerals in cardboard boxes.

Last Updated: 20th Jan 2017

By Giuliano Bettini

I recently found a strange stone in a small cardboard box. A box of matches. Inside were fragments of tourmaline, schorl, a fragment of orthoclase, and a strange quartz.
On the label it was written "Il Prato 96".



The strange quartz has quickly revealed as ... a petalite. A small chunk of slightly colored petalite. The whole piece is translucent when backlit, and it has many internal “rainbows”, good indicators for cleavage.

Here below.



Other images.

Internal rainbow
Internal rainbow
Internal rainbow
Internal rainbow
Internal rainbow
Internal rainbow


Partly backlit
Backlit
Partly backlit
Backlit
Partly backlit
Backlit


and the full specimen as a heart, "the Stone of Intent", "Stone of the Angels":



-------------------------------------------
“Il Prato” is the name of the locality in which is the Rosina vein.
So quickly I went looking in another cardboard box containing the stones of the same mission.
And I found many other petalite specimens.
First of all, a quite big stone which I named “petalite grosso”, big size petalite.

5x7x9cm
A close up view, FoV 4cm
5x7x9cm
A close up view, FoV 4cm
5x7x9cm
A close up view, FoV 4cm


Here a detail: transparent naturally etched petalite.



-------------------------------------------
As a second one, I found a medium size stone, which I named “petalite medio”. It has many petalite fragments, masses.
Among others, it shows the πέταλα, Italian “petali”.
Here is:



πέταλα, FoV 2cm
πέταλα, FoV 3mm
πέταλα, FoV 2cm
πέταλα, FoV 3mm
πέταλα, FoV 2cm
πέταλα, FoV 3mm


-------------------------------------------
I noticed that all these pegmatite stones were white, fresh, all with large pieces of black tourmaline.
So I went to look for the large stones that I kept …not in a cardboard box but in a crate for tomatoes and fruit and vegetables. I mean stones that had previously classified as "not important". And I found a third specimen. A broken black schorl on a piece of white orthoclase and inside, some petalite masses.

Full specimen
Close up, FoV 5cm
Full specimen
Close up, FoV 5cm
Full specimen
Close up, FoV 5cm


The image here below clearly shows cleavage



-------------------------------------------
Orlandi, Pezzotta, about the petalite:
... in all these veins (eg. Rosina) numerous crystals of petalite were found......
Ref: Orlandi, P., & Pezzotta, F. (1997). Minerali dell'Isola d'Elba. Edizioni Novecento Grafico, Bergamo.
Yes, it's true. Although I have not found crystals, but masses. (Findings of the ‘90s).

About the name petalite:
Ref: d’Andrada, J. B. (1800). Kurze Angabe der Eigenschaften und Kennzeichen einiger neuen Fossilien aus Schweden und Norwegen, nebst einigen chemischen Bemerkungen über dieselben. Allgemeines Journal der Chemie 4: 28—39.
Contains the original description of the mineral petalite.

















Article has been viewed at least 1510 times.

Comments

I did some researches on the name "petalite". I think it worthwhile to put them here.

The original description of the mineral petalite can be found here:

Ref: d’Andrada, J. B. (1800). Kurze Angabe der Eigenschaften und Kennzeichen einiger neuen Fossilien aus Schweden und Norwegen, nebst einigen chemischen Bemerkungen über dieselben. Allgemeines Journal der Chemie 4: 28—39.
http://rruff.info/rruff_1.0/uploads/ajc4_28.pdf
At page 10/13 of the pdf:
“Das Gewebe ist schuppigblätterig. Die blätter sind sehr klein, klein und groß, durchaus stark mit einander berwachsen.”

The same, in French: d'Andrada (1800). “Des caractères et des propriétés de plusieurs nouveaux minérauxde Suède et de Norwège , avec quelques observations chimiques faites sur ces substances". Journal de Physique, de Chimie, d'Histoire Naturelle et des Arts. Tome 51.
http://www.biodiversitylibrary.org/item/29658#page/256/mode/1up
At the pages 244-245 (Text):
“Sa texture est lamelleuse; les lames sont petites et fortement entrelacées les unes dans les autres…

So, here d’Andrada says nothing about the choice of name. (D'Andrada knew twelve languages, he could speak four….). He only says:
…..The texture is lamellar. The leaves are very small, small and large, and quite strongly interlaced in each other ...

In modern languages, πέταλον translates as:
English "petal"
Portuguese "pétala"
Italian "petalo"
Spanish "pétalo"
French "pétale"
Swedish "petal"
German "blütenblatt"

In ancient Greek, “Handwörterbuch der griechischen Sprache”. Greek-German dictionary by Wilhelm Pape (1880):
http://images.zeno.org/Pape-1880/K/big/Pape-1880----02-0604.png
πέταλον translates as: ”Das Blatt der Bäume” eg. the leaf of trees.

Conclusions:
1-petalite in modern languages reminds "petali", "petals" and so on;
2- as root of the name, in ancient Greek πέταλον translates as "leaf".


Giuliano Bettini
21st Jan 2017 11:49am

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