Pink Quartz

 

last modified: Friday, 29-Jan-2010 00:57:08 CET

Document status: complete


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Although pink-colored crystals from Newry, Oxford County, Maine, U.S.A., was already mentioned by Dake, Fleener and Wilson in their book "Quartz Family Minerals", published in 1938[1], it was not until its "re-discovery" in Brazil in 1959 that pink quartz got widely known. Pink quartz was introduced as "rose quartz that comes in crystals". Meanwhile it is generally accepted that pink quartz is an independent quartz variety, although there is some disagreement about whether to name it differently.

Pink quartz and rose quartz differ in a number of properties

- the cause of their color is not the same,
- pink quartz is sensitive to light, while rose quartz is not
- both varieties form in different environments, and
- pink quartz develops crystals while rose quartz does not.

Hence it has been suggested by Hidemichi Hori on the 22. Tucson Mineralogical Symposium and in a following publication (Hori, 2001) to officially distinguish pink quartz from rose quartz. Rykart (1995) also uses different German names for both varieties, Rosenquarz for rose quartz and Rosaquarz for pink quartz. You will nevertheless rarely see pink quartz labeled as such on a fair or in a museum, in most cases it will also be called "rose quartz".

The image shows pink quartz from Minas Gerais grown on smoky quartz. Pink quartz is quite rare and one of the more expensive quartz varieties. It is not used for lapidary works, of course, and is only sold to collectors.

 

Specific Properties

According to Maschmeyer and Lehmann (1982), the color is apparently caused by small amounts of aluminum, Al(+3), and phosphorus, P(+5), built pairwise into the crystal lattice to replace Si(+4), and subsequent high energy irradiation. In a sense, two electrically neutral SiO4 groups are replaced by one AlO4- and one PO4+ group[2]. Pink quartz is often accompanied by phosphate minerals, like eosphorite, (Mn,Fe)Al[(OH)2|PO4]•H2O. Many specimen show parallel grown crystals. Pink quartz is translucent to transparent, but rarely clear.

Pink quartz exhibits a weak dichroism, with the color changing from darker to brighter tones.

Pink quartz is very sensitive to light and will pale quickly in direct sunlight. This is an indication that the color is due to color centers whose formation appears to be triggered by high energy radiation.

Pink quartz typically comes in roughly parallel-grown groups of small crystals. An individual crystal measuring 2 cm can already be considered large.  

Occurrence

Although pink quartz has so far only been found in pegmatites, it forms in a hydrothermal environment, at high temperatures, but from a watery solution. It can frequently be found grown on smoky quartz crystals, usually parallel to the underlying smoky crystal.


 

Locations and Specimen

Pink quartz was first found in Brazil in 1959 which is still the main source. There are some reports that indicate that it had been found in pegmatites in the U.S.A. earlier in the 1930s[1]. Specimen seem to come mostly from Minas Gerais, from Linópolis, Galiléia, or Governador, for example. I have once seen an offer for a specimen from Situa da Conquista, Bahia, Brazil, in an ebay auction.

Pink quartz that is very similar in appearance to Brazilian specimen can be found in pegmatites in Maine, U.S.A, for example in the Mount Mica Mine in Oxford County.


Brazil


10mm  
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These  pink quartz crystals from Governador, Minas Gerais, have grown epitactically on a smoky quartz crystal that is slightly corroded and covered with a white crust. This is the same specimen as the one in the picture on top of the page, but slightly turned so one can see the stair-step like growth pattern on the crystal faces that indicate the internal lamellar structure.



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A  specimen with distorted and intergrown crystals from Galiléia, Minas Gerais.



5mm  
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These  translucent crystals from an unknown spot in Minas Gerais seem to radiate from a common point on the rock matrix. The crystals are translucent, with a roughened surface. Again, the crystal faces show a stair-like pattern like the ones in the first specimen.



5mm  
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A  small group of parallel grown, almost transparent pink quartz crystals sit on matrix next to a muscovite crystal (the shiny plate on the right side). From an unknown locality in Minas Gerais.


 

Further Information, Literature, Links

Footnotes

1 Bill Barr, personal communication. There are other reports about an earlier find of "crystalline rose quartz" at Newry, Oxford County, Maine, U.S.A. by Hurlbut, 1970.

2 The notation for AlO4- and PO4+ looks wrong, and one might suggest that the correct notation would be AlO45- and PO43-, but these are not isolated ions, these are groups covalently bound inside a macromolecular structure.

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