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ploum · Joined: 12 Nov 2007 Posts: 1393 Location: Near Annecy

I show just some specimens from Munich show 2010 for the moment...

Carles Millan · Posted: Nov 05, 2010 09:02 Post subject: Re: Collection of Frédéric Hède

Luiz Menezes · Joined: 10 Dec 2009 Posts: 140 Location: Belo Horizonte

The "Apatite Stalactite" from Shigar is very interesting: it looks very similar to some apatites found at the great pocket of June/2007 at the Sapo mine (object of my article published at the Sep.Oct/2008 issue of The Mineralogical Record): 2 stacks of parallel crystals crossing each other at an angle.

When I saw those apatites from Sapo I thought this could be due to twinning so I sent samples to Pete Richards but he measured the angles between the 2 stacks of crystals and found different angles, so he concluded that this habit is not related to twinning; he discussed the matter with John Rakovan, from the University of Ohio, but they just could not get an explanation for that weird habit.

Another interesting feature on those "snake-like" apatite crystals from Sapo is that the center is hollow (and there are crystals faces inside as well as outside); I discussed this thing with David London (University of Oklahoma) during the 2008 Tuscon Show ans on this opinion the hollow center might be the result of a very rapid growth (similar with what happens on several types of "hopper" crystals and also on "skeletal" quartz);
he added that crystals like the 30 cm long "Apatite Snake" from Sapo might have been formed on a matter of minutes!

So I would like to ask Ploum if your specimen is also hollow; it is by sure not a true "stalactite"; I could find out that several other locatities have produced similar apatites:

- Palermo mine, New Hampshire - stacks of lihgt gray opaque crystals crossing at an inclined angle; there is a very narrow hollow center
- Fazenda Campolino, Medina, Minas Gerais: clusters of yellow transparent crystals, also formed as 2 stacks of parallel crystals crossing each other at an inclined angle; on this case the crystals are solid, not showing hollow centers
- one pegmatite in Rio Grande do Norte state, Brazil, poduced a small lot of light pink apatites showing these 2 stacks of crystals with hollow centers
- one specimen displayed by Mountain Minerals at the 2008 Denver Show, from Pakhistan, was a "snake" of light purple crystals growing above a quartz crystal and showing the 2 stacks; it was not possible to see if the center was hollow

As I was invited to make a presentation, at the 1st. International Mindat.Org Conference next July at Poland, about the Apatites from Sapo mine, I would like to talk about this habit on my presentation, so I would like to ask all members of the Forum that possess or have seem apatites similar to these to send me photos and more information about them.