2
$\begingroup$

Does anyone know what these white crystals are?

As you an see they are growing out of some floor tiling in my house. They have been appearing for some years now out of the floor, which is cleaned fairly regularly (at least, I assume so, since my cleaner does it!). They may appear more frequently when the weather is humid.

For scale, the tile is 20cm each side. The crystals form light fluffy heaps, rather like snow and would be a few millimeters in height.

My guess is that they could be common salt, or possibly something connected with the bleach or cleaning products used on the floor. The latter case prevents me from trying the taste test to prove the former.

White crystals

$\endgroup$
4
  • $\begingroup$ To me, this looks more like the salts washed out from concrete (or brickwork, or whatever is beneath those tiles), akin to the thing known as "wall saltpetre". $\endgroup$ Jun 7, 2016 at 18:25
  • $\begingroup$ Does is give bubbles with vinegar? en.wikipedia.org/wiki/Efflorescence $\endgroup$
    – aventurin
    Jun 7, 2016 at 18:44
  • 2
    $\begingroup$ No bubbles in vinegar. $\endgroup$
    – rghome
    Jun 7, 2016 at 19:41
  • 1
    $\begingroup$ Having Googled it, it seems probably it would be wall saltpetre. I had a soil pipe break under the house a few years back and the ground would likely have become saturated with a good source of water, potassium and nitrogen, not to mention the ammonia in cleaning agents. I guess the tiles must be porous, especially where the surface is damaged, as in the picture. $\endgroup$
    – rghome
    Jun 7, 2016 at 19:50

1 Answer 1

1
$\begingroup$

This is probably efflorescence, i.e. salts that are first dissolved from the mortar or other components of the floor and then recrystallize on the surface of the floor when water evaporates, see e.g. https://www.ceramictilefoundation.org/blog/understanding-efflorescence-ugly-white-powder-on-tile.

According to the source above, if there are soluble components in the floor and water moving to the surface, these crystals are able to form.

Wikipedia has the following definition:

In chemistry, efflorescence (which means "to flower out" in French) is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or occasionally in another solvent.

According to the wikipedia article, there is primary and secondary efflorescence, and a variety of substances that crystallize.

My guess is that they could be common salt, or possibly something connected with the bleach or cleaning products used on the floor. The latter case prevents me from trying the taste test to prove the former.

In this context, the term "salt" does not typically refer to table salt, but could include a wide range of highly toxic substances. Getting rid of the crystals will require different methods depending on the nature of the crystals. It seems more likely that the source of the salt is in the floor rather than a cleaning product.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.