Andesine gemstone

What is Andesine?

Andesine is a silicate mineral, a member of the plagioclase feldspar solid solution series. Its chemical formula is (Ca, Na)(Al, Si)4O8, where Ca/(Ca + Na) (% Anorthite) is between 30%-50%. The plagioclase feldspars are a continuous solid solution series and as such the accurate identification of individual members requires detailed optical study, chemical analysis or density measurements. Refractive indices and specific gravity increase directly with calcium content.
Andesine feldspar is composed of 50-70% albite and 30-50% anorthite. 

Name and discovery

Andesine was first described in 1841 for an occurrence in the Marmato mine, Colombia. It is named after the Andes mountains of South America. The name is for the Andes due to its abundance in the andesite lavas in those mountains. 
Andesine is found in a range of colours, from red, honey-red to orange, yellow, champagne and green. In the early 2000s, red and green gemstones began to be marketed under the name of 'Andesine'. After some controversy, these gemstones were subsequently discovered to have been artificially-coloured.

Occurrence

Andesine occurs in intermediate igneous rocks such as diorite, syenite and andesite. It characteristically occurs in metamorphic rocks of granulite to amphibolite facies commonly exhibiting antiperthite texture. It also occurs as detrital grains in sedimentary rocks. It is commonly associated with quartz, potassium feldspar, biotite, hornblende and magnetite.

Andesine Healing Properties

As a protective stone, wearing andesine jewellery or simply carrying the stone around will prevent the release of necessary energies while also acting to deflect undesirable energy. Use when around particularly negative people or situations. Wearing a labradorite pendant is beneficial for sensitive people.
Like all metaphysical crystals andesine gemstone can impact the mind, thought-patterns, and psychological well-being. This stone acts to connect the intuition with the intellect. What effect does this synergy have? It facilitates creative thought, which is ideal for innovators, therapists, writers, and any work where the combination of concrete thoughts and deeper awareness is appreciated.

Physical Properties of Andesine

Chemical Formula(Na,Ca)Al1-2Si3-2O8
ColourRed, Green, Yellow, Orange, Pink, Multicoloured
Hardness6 - 6.5
Crystal SystemTriclinic
Refractive Index1.560 - 1.568
SG2.69 - 2.70
TransparencyTransparent to translucent
Double Refraction.008
LusterVitreous
Cleavage2,1 - basal ; 2,1 - prismatic ; 3,1 - pinacoidal.
Mineral ClassPlagioclase feldspar (Also see the minerals Andesine and Labradorite))