I thought that I should re-visit this thread to clarify something. After I posted here a few weeks ago I added some of the inexpensive Princess Auto blasting garnet to a couple of tanks, and was fairly happy with the results. The new garnet was the typical reddish colour that I expected, and the sand was very fine in texture, much finer than the pool filter sand that was already in use. The mixture needs to be stirred up periodically, during a vacuuming of the substrate or otherwise, to keep the two types of sand mixed. It appears as though the finer garnet sifts down between the granules of PFS, filling the interstices between grains and eventually collecting near the bottom. I suspect that if it were never stirred, or mixed by fish or vacuuming or whatever, that the garnet would be pretty much invisible beneath the surface of the PFS.
But here's the kicker: I liked the colour of the garnet when added to the PFS and picked up another couple bags yesterday while in the city. This afternoon I tore one open and was a bit miffed to find that the sand inside was still that nice fine grain structure...but it was dark gray, approaching black in colour! Still looks good, in fact I probably prefer the look (the PFS/black-garnet mix takes on a medium-to-dark mottled brownish colour, depending upon the proportions), but if you are looking for that classic dark red colour you might be very unhappy.
The bag has no indication on it of the colour of the sand inside.