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Inside the giant gypsum crystal cave in Naica mine

Photo Source : R.D. Fisher (?)

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Gypsum - Gips - Plâtre - Yeso

North America : Mexico : Free standing gypsum crystals up to 12 m size in the Naica lead - zinc mine

Coordinates : 27°50'N , 105°29'W : Naica Mine, Chihuahua, Mexico

The Naica mine with its enormous gypsum crystals may well be called the "Queen of the Giant Crystal localities". Giant crystals in general are exactly this : of remarkable dimensions ! But they are not necessarily nice or esthetic in the common sense and in fact they only rarely display free growing crystals. In Naica they do ! And all what you ever imagined about giant crystals in the interior of the earth, about enormous vugs filled with glittering crystals so large, you can walk among them, comes true in Naica ! This is the place to be for the real giant crystal enthusiac and quite frankly I would be glad and honored, if I ever have the opportunity to visit this place.

Though the Naica mine is no show mine, but still a working and producing lead - zinc mine owned by the Penoles Company. Continous mining goes on since more than a century and in 1910 the first of several crystal caves was discovered in a depth of 120 m underground. This so called "Cave of the Swords" contained extraordinary large swordlike selenite (gypsum) crystals up to 2 m size. The cave supplied large quantities of large scale specimen with magnificient "herring bone structure" selenite crystals to major mineralogical and collections world wide. It is a single huge chamber about 70m in diameter and is still acessible to geoscientists and even - as far as we know - to the public. A narrow winding path leads to the forest of crystals, which however have lost much of its luster and splendour over the decades.

In 2000 another crystal cave system was discovered at 300 m depth, even much more spectacular than the original discovery back in 1910. This newest discovery was named the "Cave of the Crystals" and it turned out to be one of the most spectacular geological and mineralogical discoveries ever made ! In fact it is a complex system of caves orientated along a geological fault, which yield free growing gypsum crystals up to 12 m size (!) and 2 m diameter.

As the initial temperature inside the caves was 60°C and the humidity 100%, a detailed exploration of the caves proved extremely difficult. There is the story about a mine worker, who tried to steal some of the magnificient crystals shortly after the inital discovery, but was overwhelmed by heat, humidity and the low ogygen content of the cave atmosphere, lost consciousness and was found literally cooked ny his fellows some days later...

That said, conditions in the caves are much more hospitable now and a lot of photos exist on the web showing cave explorers posing in T - Shirts within a maze of giant crystals. But serious exploration and documentation of the caves and the giant gypsum crystals still has its obstacles. Right now a group of italian speleologists - the Laventa group - has started a large scale scientific mapping project, using state of the art technical equipment to tackle the still hostile environment of these caves. Please have a look here for more information of this venture including an online diary.

The discovery of the giant gypsum crystals at Naica has triggered a wealth of geological research on this subject with the first papers published only recently. For more information please visit our Reading Room. More scientific literature is likely to be published within the near future.


The Naica gypsum crystals in a nutshell :

Mineralogy :

Gypsum, possibly some sulfide minerals

Crystal Size :

mostly freestanding prismatic crystals up to 12 m

Geology & Origin :

Possibly hydrothermal replacement of limestone by sulphuric acids, more research is certainly warranted

Current status :    

Active mine, access to upper crystal caves for tourists possible, access to lower crystal caves remain restricted

Remarks :

Spectacular freely developed (!) gypsum crystals up to 12 m, possibly the largest in the world


Other notable & famous gypsum occurences :

Note : Gypsum is a very frequent mineral and even large gypsum crystals are by no means uncommon. There are however some outstanding occurences, namely :

- Gypsum crystals of up to 12 m or are rumoured to occur at other mexican localities such as the Caverna de Santo Domingo, Santa Eulalia district.

- Giant clear gypsum crystals up to 7 m are known from the Debar gypsum mine Macedonia.

- The "Gran Geoda" of the Pilar de Jaravia mine, Spain with large, clear gypsum crystals.

- Enormous crystals of gypsum are reported from the Braden and the El Teniente Mine, Chile...possibly even the largest of the world.

- Perfect crystals up to 1 m are known to occur in the Raura mine, Lima Department, Peru.


Historic photo of the Cave of the Swords in the upper levels of the Naica mine

Photo Source : FOSHAG, W.F.(1927) click here for publication


Giant gypsum crystals up to 12 m in the lower levels of Naica mine

Photo Source : unknown

Explorer in a maze of giant gypsum crystals

Photo Source : R.D. Fisher



Resources and relevant weblinks :

For more information on the mineral gypsum please look at, Webmineral and the german Mineralienatlas.

Although long known as a true crystal treasure trove, the discovery of the new Cave of the Crystals makes the Naica mine even more famous and there is some good online documentations about the crystal caves; some of which you may find here. There is also a book out by R.D.Fisher, which you can find here.

A large amount of photos of the caves - some much better than those displayed here - can be found by googling around for "Naica" including an excellent calendar of Naica, which you can find here.

FOSHAG, W.F. (1927) (see image above) gave a good description of the first crystal caves in Mexico and described the crystal morphology in detail. His publication can be found in the Reading Room.

The recently discovered gypsum megacrystals of the "Cave of the crystals" are described in several papers and publications, which you also can acess in our Reading Room

...and do not forget to visit the Laventa Naica Crystal Cave Project including its online diary here.




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