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?
Below are some preliminary notes I have made about Andalusite. This entry and thread has been made as a place holder for information that you will hopefully contribute about Andalusite. It should be in no way be thought of as a claim I have staked out to write about this mineral, and in fact is an invitation for someone to step forward and create the article about this mineral. If you are so inclined and have questions about the format that such an article should have, go the The welcome topic at the top of the Best Minerals forum and read what has been posted there. Also take a look at some of the more mature articles that have already been written like Rhodochrosite, Adamite, Millerite etc. You will need also to pick out other images of Andalusite that will go into the article.
Andalusite
Al2SiO5 Orthorhombic, Tirmorphic with Kyanite & Sillimanite
Andalusite Display collections.
Al2SiO5
Andalusite is a common metamorphic mineral found in clay slates, and argillaceous schist, especially in connection with granitic intrusions. It is often associated with sillimanite, kyanite, iolite, garnet, corundum and tourmaline. There are many localities for this mineral and only some of the ones that produce good crystals are mentioned below. If you have a favorite andalusite locality that I have not mentioned below, tell me about it and send an image and I will include it here. I have certainly skipped over a number of them. When localities produce crystals, they are usually prismatic and square in cross section. Of the localities that produce crystals of the variety called chiastolite, they are rough and the approximate shape of cigars and enclosed in rock. The chiastolite variety has a distinct internal structure or zoning caused by “a regular arrangement of carbonaceous impurities through the interior, and hence exhibiting a colored cross, or a tesselated appearance in a traverse section.” Localities that produce freestanding crystals are rare and specimens from most localities must be carefully worked in order to remove rock from around the crystal so as to show them to best advantage. Most specimens, especially the chiastolite variety are also cut and polished to show the cross like designs in the interior of the crystals. Most serious collectors would not put one of these in their collections but they are common in educational exhibits. You should be able to get a good chiastolite for less than $100 if you want one. The ones all the collectors want are the well formed gemmy crystals from Brazil. “Faceted stones from 75 to 100 carats from Brazil are known. Faceted stones over 20 carats are extremely rare.”1
1 Encyclopedia of Gems, 1st edition, Joel Arem p 5.
Andalusite
Australia
South Australia, Bimbowrie, Mt. Howden. Crystals of chiastolite to 15 cm have been found on Mt Howden. These are found frozen in rock and need to be carefully exposed by working them partially out of the rock to display them to best effect or to grind and polish the crystals in the rock to show the internal patterns of the twinned crystals.
Andalusite
Austria
Tyrol, Selraintal, Lissens Alp. “In large crystals with kyanite....”1 These crystals are quite rough looking as you can see from the one pictured here that is in the British Museum of Natural History. Today, most collectors would not put such a specimen in their collection.
1 Dana's Textbook of Mineralogy 4th edition, W.E. Ford, p616.
Andalusite
Brazil
Bahia, Chapada Diamantina, Serra da Mangabeira. Here in pockets in the bed rock are concentrated pockets of gravel that are rich in pebbles of cassiterite but sometimes also contain small pebbles of Andalusite, some of it gem grade. The gem rough found here are almost always rounded translucent to transparent pebbles that are strongly pleochroic; yellow brown to yellow green. Rarely stones are found that are an intense green and are given the varietal name of viridine. The color is caused by manganese. These gem gravels will rarely produce a stone of more than a cm in size. Gem pebbles are also reported to have come from near Santa Tereza in Espirito Santo State. The small gem crystal pictured here was simply labeled Bahia but it is probably from the Chapada Diamantina area. This little crystal would easily cost you $500 to $1000 if you are lucky. Chapada Diamantina is a quartzitic highland plateau running north and south and located east of Salvador in central Bahia. This area is known as the Serra da Mangabeira and located near the small towns of Livramento do Brumado and Paramirim which are 66.5 & 130 km respectively north of Brumado.
Andalusite
Minas Gerais, Cruzeiro Novo (county), Santa Maria. “Sometimes in gem color and transparency, nice crystals.,”1 . Green or tan transparent crystals, mostly single but sharp and gemmy up to 5 cm were found but most were less than 2 cm. The best of these transparent crystals were from Minas Gerais, and if you want one you will have to be satisfied with a thumbnail size specimen. It could cost you several hundred dollars or more if you can find one.
1 Mineralogical Record, Vol. 2, 1971, p10.
Andalusite
China
Henan, Xiang County. In Xiang County near the border of Shanxi Province, there is a locality for the chiastolite variety of andalusite that is so abundant that they are cut up by some of the lapidary factories into polished slices showing the tessellated interiors of the crystals and into balls usually over 3 cm in diameter. We have sold hundreds of these things. I am not entirely sure of this locality but think it is accurate.
I will give a more specific locality if I can find one.
Andalusite
India
Andhra Pradesh, Nellore District, Saidapuram. “A train ride some 125 km northward from Madras brought us to Gudur. From there it was a 12-km trudge westward along a dirt road to Saidapuram. Along the way, the road crossed some north-south trending low hillocks composed of staurolite-kyanite schist. I was astonished to find that I could simply pick up from the ground impressive crystals of staurolite, which had weathered out of the schist. The crystals, dark reddish brown in color, were the largest and best formed I’ve ever seen. They had the classic form of a textbook diagram of staurolite, up to 8 cms in length and 5 cms across. Unfortunately, the luster was subvitreous to dull, so I didn’t see enough commercial potential in them to revisit the locality after I became a mineral dealer 20 years later. The specimens collected there I also donated to the Harvard Museum. Kyanite blades from that location commonly occurred in thick blades 3 cms in width and up to 30 cms in length with a rich royal blue color, but none would qualify as specimens worthy of exhibit by American collectors.”1
1 Rustam Kothavala, personal communication 1992.
Andalusite
Italy
Tuscany, Elba, Grotta al Guerrino. “Recently a few beautiful specimens have been collected…with pink, 3 to 4-cm crystals in a granite matrix.”1 Grotta al Guerrino is near the much more famous San Piero in Campo locality that is famous for elbaite. I have never seen any of these but sure would like to.
1 Mineralogical Record, Vol.16, 1985, p356.
Andalusite
United States
California, Imperial County, Ogilby Railway Crossing, Cargo Muchacho Mountains, American Girl Mine (Au). Thousands of crystals have been found at this locality, mostly imperfect because of the perfect cleavage and the need to break them from the rock. They are very brittle. The color is generally a opaque dark gray to brown. Rarely stones have been cut from the material, but stone larger than 1 carat are rare. A rough and cut example was donated to the San Bernardino Co. Museum some years ago by Bill Besse who has dug as much as anyone at the locality. The Minerals of California gives a locality of Bluebird (Vitrefax) Mine and there is andalusite there, but by far the better locality is the American Girl Mine which is located about a mile east in the American Girl mine. The American Girl mine is a big open pit mine and underground but the andalusites are found in the part of the American Girl mine that is small pit that was worked prior to the development of the large open pit mine. This pit is about mid way between the big open pit of the American Girl mine and the Bluebird Mine. 1
1 Bill Besse, Personal communication 2003
Andalusite
California, Los Angeles County, Beverly Hills. In crystals in slate up to 15 cm long. These are pretty ugly creatures that only a mother could love, but remember Beverly Hills is right next to Hollywood and that has got to count for something!
Andalusite
California, Mono County, Inyo Range, Champion Mine. In rough prismatic crystals and clusters up to 10 cm. The crystals are pale green or yellow-brown or white and look kind of moth eaten and many are partially altered to quartz. This mineral was commercially mined here for industrial purposes.
Andalusite
Pennsylvania, Upper Pridence. “ two sharply-crystalized, long-prismatic, “andalusite” clusters.”1 These were part of the Joseph Leidy collection (late 19th century) at Swathmore College that Arthur Montgomery rescued from a basement at the college and are now at Lafayette College in Pennsylvania. If Arthur was impressed with them they must be good though there must be only a handful of such specimens still in existence.
1 Mineralogical Record, Vol.1, 1970 p38.
Andalusite
South Dakota, Custer and Pennington Counties, Berne. Short prismatic blocky crystals up to about four inches. The crystals are occasionally terminated, not free standing and found growing in a mica schist?. The crystals are brown to brownish pink and easily collectable. They are abundant if you want to take the time to collect them. All the crystals are internally cracked but somewhat translucent on their edges. Mica flakes are often incorporated into the surfaces of the crystals giving them a somewhat sparkling look. The locality is located right on the county lines. Berne is a little gost town. The locality is located about 2miles north of Oreville Lake.1
1 Chris Korpi, Dana Point, California, personal communication 2003.
Andalusite
Virginia, Campbell County crystals “blocky in habit and up to a half meter in length! Some are partially replaced with kyanite and paragonite” These are big butt ugly crystals.
Rock Currier
Crystals not pistols.
Edited 1 time(s). Last edit at 05/15/2009 08:46PM by Rock Currier.
