Monday, September 28, 2009

Blue rock of death

A few weeks ago, V** arrived early enough that she overlapped with A before he left for campus. Or maybe he was late. That detail is fuzzy but this one is not--she wanted to ask him about the blue rock of death.

A few weeks before, she had been cruising a yard sale & found a shiny, turquoise-y, glassy-looking rock. The seller of the rock said it was for a a fish tank & V** said "I have a fish tank!" & she bought it. Because it was shiny. & turquoise. & looked like glass.

She went home & forgot it in the cab of the truck for a day or two. Then she brought it in, cleaned it off & put it in her freshwater tank. By morning all the fish were dead.

She was shocked, horrified & very upset. She was scooping the bodies when she saw a small, pitted, ugly thing at the bottom of the tank & asked herself "what the f*ck is that?" It was the blue rock of death, but its appearance had changed dramatically.

She dealt with the bodies, left the rock & went to work. When she got home, the plants were starting to look, well clear. Photosynthesis had clearly stopped & they were losing their green. She took the blue rock out, put it in a bag & I am sorry to say it is now sitting on my front step.

This is what we know: the bottom of the tank is certainly richer in nitrogen than any other part of the tank. Because it is sizable, she usually cleans it by pumping it out rather than transferring fish, scoping out water, etc. so it might be even higher than most other healthy fresh water tanks.

V** thought that the pitted surface might be something that had 'grown over' the rock, but A says not. he is pretty sure the change is to the surface itself.

We would know more but A keeps forgetting to borrow a Geiger counter (would you believe he has had reason to borrow one in the past? Well, he has).

So does anyone know what the blue rock of death might be? Does anyone have any questions about the blue rock of death? Does anyone want me to send them the blue rock so they can examine it more closely ? That would last one be ideal, actually.


  1. Hi, browsing via the QuiltAlong. I asked my Dad, who's a mineralogist, to take a look at your post. Here's his response (I guessed cuprite):

    Not many blue minerals, and most of them contain copper, so a good guess. The other characteristics would have to be: vitreous luster(assuming that shininess was natural), and soft or soluble in water.

    Possible candidates might be:

    cuprite, chalcanthite, chrysocolla, or azurite. Of those, only cuprite and chrysocolla can be vitreous. I'd guess the latter, but only a guess without seeing it. Too bad there wasn't a photo of it "before"!

    Turquoise is probably too hard to dissolve in water.

    It proves you should not put unknowns in your fish tank, anyway!!


    He's a rock geek but I love him.

  2. we did identify it as azurite ( & what really really sucked was she did not just pick it up off the ground-it was sold as a fish-tank rock.