Why glass used in ips flooring?

Indian Patent Stone: Glass is often traded out for the agregate stone in cement applications. It is strong and hard & readily available & it can add a unique look to the finished floor that cannot be achieved with Gravel.

This is what another answers question says about the composition:

Where on flooring subjected load is not more the flooring should be laid as per requirement of IPS. IPS is an Indian Polished Stone or Indian Pattern Stone. The base for IPS should be made very well compacted. The compaction of filled up base can be achieved by means of mechanical compaction. Over compacted base, lean base of either brick bat or sand should be laid. Over it a 75mm thick layer of plain cement concrete or plain lime concrete is to be laid. Now a layer of 100 mm thick reinforced cement concrete is to be laid. The concrete should be laid in two layer of 50 mm each. Each layer should be compacted, vibrated to achieve dense & monolithic concrete. The minimum cement concrete content for the concrete should not be less than 300 kg/m3. The final finishing of the IPS should be made with neat cement slurry, which is to be floated and finished perfectly to have a smooth finish.