Wednesday, 23 December 2009

Sal Mirabilis!

Mornin' all.
For those who can't sleep for worrying about what's going to turn up in the green gloop, here's a quick note to let you know. After the first day, long clear needles started appearing on the string - up to 2 cm long. As soon as I got the camera out, though, they'd all vanished!

This does happen, sometimes - things crystallise, and then dissolve again. This time, though, it was more mundane - the crystals had got too big and fallen off!

So, a quick decant later, and here they are, growing together in the bottom of the beaker:

The green is just colouring from the solution itself, and don't worry about the brown blob on the right - that's the remains of a paperclip I dropped in for fun. As I might have said, it's good stuff, this!

Now, I know you're dying to know what this is, so here you go:

The crystals have a parallelogram-shaped end that slopes to one side, but are otherwise long thin prisms. Of the possibilities from what went into the gunk (sodium chloride, copper sulphate, and a bit of aluminium) this can only be...

(hydrated sodium sulphate, Na2SO4.10H2O)

Nice name for a very nice little crystal. Now, since we've taken some sodium and sulphate ions out, there should be a bit of copper chloride waiting for us after Christmas... that'll be fun! Unfortunately it's doomed to crumble into a white powder once it loses water. But it does make an exceedingly good purgative, as discovered by Glauber in 1645... and hence the name! Miraculous indeed! Any volunteers?
Have a lovely sparkly holiday, and may Santa bring you lots of obscure mineral growths that you've never seen before. If he doesn't, I suggest checking his beard for them. That's where I keep mine.


  1. Dear Dr Rock,

    I am enquiring as to whether you have a vacancy for a lab assistant. I am fully experienced in electrical installation and am excellent at hand sewing.

    I await your reply, sir.

    Your sincerely,

    Igor Igorsson

  2. Well, now - my very own Igor! Thanks you kindly - what a delightful offer. I'm not entirely clear what the sewing will be useful for, but I suppose some of the needle-like crystals are quite bendy, and would certainly fit through the eye of a needle... although I really wouldn't recommend starting on asbestos fibres.

    In general, though, I always have room for a lab assistant. Are you any good with a blender? Had any practice at cave painting? Please send me your cv by the normal owl-mail procedure (wrapped around an interesting rock, of course), and I'll see what I can do.

    Yours with sparkly bits on,
    Dr. Rock

  3. I've just found out that mirabilite should dehydrate to thenardite (Na2SO4 rather than Na2SO4.10H2O)... and thenardite is fluorescent! My assistant Kathy is getting some UV lamps, so I think this might be interesting...

  4. Dear Doc Rock - Where do you conduct all your experiments?

  5. Well... I must confess that's something I tend to keep quiet about when the wrong people might be listening! Luckily my other half, Dr. Sock, thoroughly approves of these things, so the more hazardous ones I can do at home. I get up to quite a lot in my lab, though - you'll be able to see that once the gallery is ready. With any luck, there will still be some crystals growing in a corner somewhere!

    Of course, I can't possibly let on where the gallery actually is! I only found the place by accident, and I can't afford to be disturbed until then. There are people - believe it or not! - that might want to interfere if they knew about it - so sshhh! It's somewhere in one of the Leeds museums, but that's as much as I'm saying.

  6. Hi again Doc Rock - Thought I saw you on a bike in the centre of Leeds - was that you?

  7. The blog is very complete and very helpful the pictures you used to understand, really amused me much, but not so much how to use Generic Viagra than that if it's fun, but if I really like your blog!

  8. Hi good day ! nice post you have . It's very nice , I have plan to setting up my garden can you give me an idea or steps on how to make it beautiful. i have heard some garden accessories such as garden spinners , wind chimes , wind spinners and many more . I want to try this things in my garden but i don't know how to get the right accessories . I hope you can help me . thank you .