Evaporite needle crystals

Brains

Brains

Well-known member
I am sure many of us have noticed in underground places, particularly old mines, tunnels and man made structures, but also in natural places, very fine needle like crystals growing in mats on the walls. I had always thought of these as gypsum or selenite, possibly aragonite. I have also noticed these growths are somewhat seasonal, either growing or completely vanishing. I had heard they could be a nitrate based evaporite, rather than sulphate or carbonate, probably a hydrate. The needles seem to age in to a more nodular popcorn type surface with fewer obvious needle like features. Rarely the crystals can be up to 15mm, but more usually 5mm is a more common length
Does anyone out their have any more info, ideas, thoughts?

16114604_458616660928898_5731552302350086978_n.jpg

This poor photo from Cwmorthin shows such a mat of fine crystal needles
 
K

Kenilworth

New member
Selenite is gypsum, and is what most commonly forms cave crystals. However, nitrate minerals and crystals are sometimes found in caves. Nitrate cave minerals are indeed evaporites and very soluble in water, meaning that they are transient, as you describe, based on relative humidity.

-adapted from Forti & Hill p.157
 
AR

AR

Well-known member
Epsomite is Magnesium Sulphate, and highly soluble - it crystallises out in some parts of Nenthead, or so I've been told. I do wonder whether we see it in the Peak in the Dolomitized limestones but assume it's Selenite?
 
Brains

Brains

Well-known member
Epsomite sounds a possible candidate, but what are the nitrate minerals you refer to Kenilworth?
I am sure if there is a possibility there may well be a variety of mineral types present. The vast majority appear colourless or white, with locally a yellow stain I had thought of as iron or sulphur leaching into the area
 
Pitlamp

Pitlamp

Well-known member
Kenilworth said:
But epsomite is a sulfate...
Try tasting it.
Click to expand...

I've seen these somewhere, possibly in the Burtersett mines near Hawes.

Must admit I also always thought they were a sulphate - based on having (tentatively but foolishly) tasted them once.
 
K

Kenilworth

New member
Pitlamp said:
Kenilworth said:
But epsomite is a sulfate...
Try tasting it.
Click to expand...

I've seen these somewhere, possibly in the Burtersett mines near Hawes.

Must admit I also always thought they were a sulphate - based on having (tentatively but foolishly) tasted them once.
Click to expand...

There's nothing foolish about tasting rocks and minerals, or plants and fungi. Tasting is often an excellent aid to identification, and it is good to build a repertoire of recognizable tastes, since appearances often vary wildly within a single specimen type (so do tastes, but every tool is valuable).

Brains said:
what are the nitrate minerals you refer to Kenilworth?
Click to expand...

Darapskite forms flowers, crusts, hair, and stal. Niter and Nitratite, Nitrocalcite, Gewihabaite, and other extreme rarities are also listed by F&H.
 
droid

droid

Active member
Kenilworth said:
There's nothing foolish about tasting rocks and minerals, or plants and fungi.
Click to expand...

I'd be wary tasting plants and fungi unless you're pretty certain you know what they are.

In which case you wouldn't need to taste them.
 
Mr Mike

Mr Mike

Active member
They look like epsomite, at an earlish stage of growth. Generally they are the long thin spikey ones, needle like - and yes areas in Nenthead are covered in them. In some parts where the conditions are right and the air is still they can grow +30cm - as in the grotto in Smallcleugh.

Gypsum are the cornflake looking crystals, again plenty of those at Nenthead, hence the name of a junction in Smallcleugh, Gypsum Corner.
 
Brains

Brains

Well-known member
droid said:
Kenilworth said:
There's nothing foolish about tasting rocks and minerals, or plants and fungi.
Click to expand...

I'd be wary tasting plants and fungi unless you're pretty certain you know what they are.

In which case you wouldn't need to taste them.
Click to expand...

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. Many of the sulphide metal mines of the UK have traces of Barium and Arsenic, some being worked for these metals. Both are toxic in soluble form, and the latter forms salts that are reportedly sweet tasting. More obvious problems come from the salts of Lead, Zinc and Copper. The sulphides as they decay produce "battery acid"
Some of the evaporites discussed here are powerful emetics
Taste with caution, and spit and rinse with clean water
Enjoy!
 
K

Kenilworth

New member
droid said:
Kenilworth said:
There's nothing foolish about tasting rocks and minerals, or plants and fungi.
Click to expand...

I'd be wary tasting plants and fungi unless you're pretty certain you know what they are.

In which case you wouldn't need to taste them.
Click to expand...

Even plants and fungi which are deadly can be safely tasted. But if you are worried about them, the smart thing to do is to become very familiar with any deadly species in your area (depending on where you are, there probably aren't very many), and then avoid them and their lookalikes. This will mean that you'll skip a lot of safe things. Boletes, for example, come in many similar-looking varieties, some edible, some poisonous. I'm not worried though, and have tasted many fungi I knew to be poisonous.

 
Brains

Brains

Well-known member
I think it was Terry Pratchett who said everything was edible, but some things were only edible once.
As for tasting the like of Ray Mears will give advice on how to test plants and things to look out for.
My food tends to eat the plants for me first and convert them into beef, ham, venison etc...
 
R

robjones

New member
droid said:
Kenilworth said:
There's nothing foolish about tasting rocks and minerals, or plants and fungi.
Click to expand...

I'd be wary tasting plants and fungi unless you're pretty certain you know what they are.

In which case you wouldn't need to taste them.
Click to expand...

A useful piece of advice is: don't eat them all, always save a sample to show to the staff in the emergency room.  ;)
 
droid

droid

Active member
Some of your contributions to this fine forum suggest more than 'tasting' some 'mystery mushrooms'.... :LOL:
 
K

Kenilworth

New member
droid said:
Some of your contributions to this fine forum suggest more than 'tasting' some 'mystery mushrooms'.... :LOL:
Click to expand...

Nope. I've never experienced, or been interested in, chemical augmentation beyond that which comes with a few cups of coffee.
 
ZombieCake

ZombieCake

Well-known member
My food tends to eat the plants for me first and convert them into beef, ham, venison etc...
Click to expand...
Quite agree - I'm a vegetarian by proxy too  ;)

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.
 
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