Since 2005, AGT has been the glow aggregate market leader. We understand that in most cases, glow stones are being placed in permanent substrates such as concrete or asphalt and you need to know that they will glow – not hope that they do… Many online peddlers of glow stones, glow marble or glass glow chips say that their product will “glow all night” or “glow for over 10 hours” but the fact is – THEY DON’T!