Beware the Whisper Stock, page-116

yep. define sand.
There is a lot of different types of sand and sand grain sizes. Some will be ideal for bricks. Some will be terrible for bricks.
There is also likely a infinite number of recipes for bricks. Some will contain a lot of sand, some will contain very little sand relative to the mass or volume compared to the rest of the mix...or maybe none at all.
Modern brick making....huh, so a thousand years ago no one used sand in there brick recipes? Of course some people did, and likely there were some that didn't.
Even now there are some researches developing brick recipes that do not use sand.
Such as these bricks made from clay and wool.
No firing/kiln process needed.
http://dgml.pbworks.com/w/file/fetch/58759610/Assign%202_Materials%20Process_Team%205_%20Organic%20Byproducts.pdf

Back to dune sand....it is different to river sand.
Interesting article here that looked at using sand from the Australian desert to replace river sand in concrete recipes.
clearly there are lots of variables to consider and just because there is "sand" in the middle east....doesn't mean it will be possible to make a brick that is suitable for the HX out of that sand.
https://www.researchgate.net/profile/Mohammed_Goual/post/Is_it_possible_to_use_desert_sand_as_a_building_material/attachment/59d6313879197b807798f01a/AS%3A364974766608384%401464028173546/download/dune+sand+concrete4.pdf
From part 7 of the conclusion of that article about desert sand.
"It should be noted that, however, the test trends observedare valid only for the type of desert sand studied. For thedune sand from other deserts, the optimisation of VFP contentin DSC should be based on trial mixes."

Apologies to the forum of my first comment about bricks not being made of sand.
It was wrong and plainly stupid. It was quick comment made with not much thought as to the wording.
My thought at the time was that the main component of bricks was clay and not sand.
But of course, even that is wrong as concrete doesn't have clay in it, and concrete bricks are certainly possible and do have sand in them.