FMF - Friends of Minerals Forum, discussion and message board

[Turbo]

I'm interested to know the major areas gypsum specimens came from. Is the Cave of Giants synonymous with Cave of Crystals. I recall Cave of Swords as well. What others have their been?

[James Catmur]

This one was found in Spain, so the write up is in Spanish, but I hope you can get an idea from the photos.

https://giantcrystals.strahlen.org/library/jaravia.pdf

There is now a virtual visit you can do to the mine! That has just been written up on the Spanish side of the FMF

https://www.foro-minerales.com/forum/viewtopic.php?p=122889#122889

[Peter Megaw]

Cave of the Crystals and Cave of the Giants are synonymous. Cave of the Swords is a separate cave much higher in the mine. Chubasco is another separate famous gypsum zone at Naica...highly transparent blocky or elongate crystals on distinctive dark chocolate colored matrix.

Huge gypsum crystals were also found at Santa Eulalia, Platosa (Durango) and in the Zona de Silencio, Coahuila (classic jagged swallow tail twins to 1.5m length.

Crystals to 8m long and nearly 2m in diameter were also found at El Teniente in Chile.

[Turbo]

I have seen a few of the chocolate matrix pieces. I never knew the name of their zone. Looking at this photo I took of a case at the East Coast show, back left and front right would most likely be Chubasco by your description. Do the water clear long bladed and sword like pieces have a particular zone? I imagine they are not from the cave of swords as those are more included. All of these are being described as Naica pieces, but some do bear resemblance to specimens from other sites as you describe.

[Peter Megaw]

Turbo, had some fun with Marty on this case.

The three pieces on dark matrix are from the Chubasco Breccia.

The piece in the front left corner...matte luster and tan clay inclusions...is from a cave in Colonias, Chihuahua. These are routinely mislabeled Naica or Santa Eulalia.

The tall swallow-tail piece is classic Zona de Silencio l, Coahuila.

The ramshorn is probably Santa Eulalia...definitely not Naica

The rest are legitimately Naica

[Turbo]

I will internalize that information and correct others who label things in error. I imagine the occasional specimen labelled Cave of Crystals must be mislabelled unless you think some material was removed and made it onto the market somehow.