Sand and glass are not really the same thing, though sand is used in
the manufacture of glass. Sand is mostly the crystalline form of
silicon dioxide known as quartz. The yellow/brown colouring comes
mostly from iron oxides. Glass is made by melting sand with sodium and
other metallic compounds and then supercooling it to form a
non-crystalline solid. Glass is not nearly as hard as quartz but the
main reason for not using it as an aggregate is that it is much more
valuable than sand.

Unless you are being paid for how many zillion bricks per hour you can
lay, sharp sand is perfectly good enough for building and the mortar
will indeed be stronger than with soft sand. More importantly, if you
want to be on the side of the angels, don't use Ordinary Portland
Cement at all. Build with lime mortar, a 3:1 sand : lime mix. The
best lime to use comes wet in a plastic tub and is called lime putty
but a cheaper alternative is the bagged hydrated lime available from
all buildres' merchants. Buy it from a merchant with a rapid turnover
and empty the bag into a plastic dustbin of water as soon as possible
and then use it wet because the lime cabonates on contact with the air.