Coloured crystals emerging from concrete

[R D S]

Are you OK? This is bugging you even more than it's bugging me it would appear, I'd simply stop reading my posts.

So, in reality (I have three bags outside) if I tip the contents out of a 25kg bag of sand there's a likelihood that there'll be bits of multicoloured glass in it? That I won't notice while mixing, pouring, trowelling and painting over?

Fair enough, I came on here looking for a reason and if that's the best we can come up with so be it. As you say though, I can't accept it (I believe that's a choice i'm allowed), the area in question is about 4m long and will have needed numerous bags.

But whatever, that's me done with the topic, onwards...

[alan_m]

You may not notice

and this is with sand that doesn't stain your hands and without grey cement.

[The Natural Philosopher]

yup.

as predicted

[Theo]

So you can solve the conundrum very simply. Take a handful from a bag (making sure to get the aggregate, which might have settled), and put it in a bucket of water. Sieve out the big bits and give them a good scrub. What are they made of?

Once cleaned you should be able to identify the source - flint, limestone, sandstone, etc. Any reclaimed bits like concrete or glass will also show up.

If you can't accept the evidence of your own eyes, I'm not sure there's much we can do.

Theo