# Crystalline growths

**URL:** <https://boards.straightdope.com/t/crystalline-growths/295253>\
**Category:** Factual Questions\
**Created:** [March 19, 2005, 2:15am UTC](https://boards.straightdope.com/t/crystalline-growths/295253 "2005-03-19T02:15:15Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![gentle](https://avatars.discourse-cdn.com/v4/letter/g/eb8c5e/32.png) [@gentle](https://boards.straightdope.com/u/gentle)\
**Post date:** [March 19, 2005, 2:15am UTC](https://boards.straightdope.com/t/crystalline-growths/295253/1 "2005-03-19T02:15:15Z")

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A local deli has a glass-enclosed counter where they keep the various ingredients and condiments in plastic containers, so that the customer can point and choose what to fill their sandwiches with. The containers sit in a sort of shallow metal tub, the kind you might fill with heated water to keep food warm.

What I noticed today was that the surface of this tub is lightly sprinkled with a kind of white crystalline material looking very much like frost – clusters of little star- or snowflake-like shapes. I am fairly sure that the counter isn’t refrigerated, so I rather doubt that they’re ice crystals.

I remember having seen something similar before: When I moved into my previous apartment, the bathroom had a ceiling lamp whose cover had a similar, crusty crystalline matter that seemed to be growing on it. It might not be the same thing, though.

What’s this stuff? There’s no living matter that is crystalline, that I know of, but perhaps there’s some kind of fungus that just _looks_ that way.

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**Author:** ![gentle](https://avatars.discourse-cdn.com/v4/letter/g/eb8c5e/32.png) [@gentle](https://boards.straightdope.com/u/gentle)\
**Post date:** [March 19, 2005, 6:57am UTC](https://boards.straightdope.com/t/crystalline-growths/295253/2 "2005-03-19T06:57:24Z")

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(Could it be mildew?)

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**Author:** ![mittu](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@mittu](https://boards.straightdope.com/u/mittu)\
**Post date:** [March 19, 2005, 12:15pm UTC](https://boards.straightdope.com/t/crystalline-growths/295253/3 "2005-03-19T12:15:06Z")

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I have no idea what it could be but it occurs to me that one easy way to find out would be to ask the people in the deli 🙂

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [March 19, 2005, 2:33pm UTC](https://boards.straightdope.com/t/crystalline-growths/295253/4 "2005-03-19T14:33:50Z")

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Likely a residue from a cleaning agent. Sodium tripolyphosphate or ammonium chloride are possibilities, or it might be the salt of a detergent.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [March 19, 2005, 11:07pm UTC](https://boards.straightdope.com/t/crystalline-growths/295253/5 "2005-03-19T23:07:04Z")

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Could also be hard water residue, again from the cleaning.

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**Author:** ![gentle](https://avatars.discourse-cdn.com/v4/letter/g/eb8c5e/32.png) [@gentle](https://boards.straightdope.com/u/gentle)\
**Post date:** [March 20, 2005, 2:25am UTC](https://boards.straightdope.com/t/crystalline-growths/295253/6 "2005-03-20T02:25:30Z")

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Thanks.