That is the stuff that I am talking about.
IT DOES NOT PASS THE FIZZ TEST. I mistakenly thought that it did because of the cloudiness that the sand created in the cup. It reacts exactly the same in vinegar as it does water. Perhaps I'll do the vinegar test tonight again and post pics, if you wish. I'll also do a comparitive water test.
It has highly variable grain size and easily creates a sand storm in water - very cloudy. As I soaked it in water, the larger grains rose to the top creating a "not so fine" sand look. It looks much coarser.
I have some in the tank, with no water in it yet, if you want to look at it.
Here is another opinion. He believes that it is not Silica but Quartz...
Taken from MR....
A_n_Es SEA
Member
Join Date: Feb 2004
Location: Southeast Michigan
Posts: 32
Okay, so I bought some of this sand last night at HD (White Play Sand). The color is good and white, but the particles range from less than sugarsized to about 2 mm in size.
I looks mostly like crushed quartz, and turns very milky when mixed with water, though I didn't wait around to see if it would settle or not.
I tried dissolving some in vinegar and nothing, nada.
Findings:
its definitely not Calcium based, mostly likely quartz based from the looks
Particle sizes range from less than sugar-sized to ~2mm.
Color is fairly bright white.
Seemed to produce alot of cloudiness in water (only tried small amount)
May or may not work in an aquarium
Since it looks quartz based and not silica based, it shouldn't leach harmful silica, my theory is that it would act alot like standard aquarium gravel used in fresh water setups. That is if it does indeed settle out with time.
Probably would not be suitable for sand sifters seems to have some jagged edges on the larger pieces.
Just my observations.....thought it might be of some help.