Evaporite needle crystals

[Kenilworth]

Don't know what the fungus is like in the good old US of A but there's some pretty nasty ones over here (Death Cap, Destroying Angel, etc.) that will give you a one way ticket to a pine box.  Suppose it makes up for the lack of dangerous snakes & spiders.

Death Caps are not native US species or well established in the eastern part, and I don't know if I've ever seen one. Both they and the Destroying Angel (which is a generic term for several poisonous species present here, two of which I have tasted) are Amanitas and indeed very dangerous. I've in fact just come back from hunting for morels and chanterelles. This is beginning of the season, and I found what I expected to, nothing edible.

But back to tasting rocks. Brains wrote that:

Many rocks can be enhanced by a lick, highlighting detail not clear on a dry surface. Most rocks are inherently insoluble in the timescale of a tasting, hence tasting will only give a hint to surface contaminents or deposits.

Which reminds me of a time when I was forced to lick an expanse of flowstone in order to read 1920s pencil writing beneath it. I also commonly taste the raw sections of rocks broken while digging, or the rock flour from drilling. It would be neat to be able to identify regional limestones by taste. Minerals of course, like the crystals that this thread began with, are surface deposits, and quickly soluble.

 

[Alkapton]

Back to the original point of this thread

By far the finest cave needles I've ever seen, in fact the finest formations I've ever seen were in Ogof Capel, is it Slarlom passage?  Passage on right soon after gate.    Here is the most beatiful scene in the world!!!    There are needles no more than the width of a human hair, some over six inches if memory serves me.  They can be almost horizontal and are stable in a draught which does not seem possible.

I was once told what they are but I've forgotten, any ideas?

 

[Kenilworth]

Halite or selenite?

 

[Brains]

I doubt halite as it is so soluble and will draw moisture from the air to form brine. Selenite is a likely candidate, especially if the formations are persisitent across seasons and weather conditions, less likely might be aragonite. If however the minerals vary with seasons and weather then I guess epsomite is a good candidate. The needles I have seen are as fine as you describe and grow out into cave, non flexible and clear or white. I havent seen them as long as you describe, but you could be luckier than me!

 

[Cavematt]

For some photos of the Epsomite crystals in Nenthead that we took a few weeks ago see here:

http://yucpc.org.uk/gallery/album.php?id=950

(Photos 10-15, and yes, we know these are not technically in the Rampgill part of the system)

The needles are much longer and finer than those in the original photograph so not sure if there is any similarity.

 

[Brains]

Cracking pics, far better than my poor attempt, and I would say they are the same stuff