Finely Crushed/powdered Glass Mixing With Cement Can Make To Some Extent Light Passing Bricks?

I'll believe when I see it (or see through it).
Seriously, I've been working with concrete for 40 years and never heard that one.
There are articles about glass dust used in concrete but mainly for trcycling purposes or waste disposal. One link is included below:

Mixture Proportioning and Properties of Self-Consolidating Lightweight Concrete Containing Glass Powder | ACI Materials Journal | Find Articles at BNET (http://findarticles.com/p/articles/mi_qa5360/is_200509/ai_n21386420/pg_7)

Correction: for recycling purposes