Complex sentence: Copper oxide is still used today to colour Hebron glass, though today the raw material used instead of sand is primarily recycled glass which is gathered from local houses, brought to the factory to be smashed, and re-melted.
Split into simpler sentences: Copper oxide is still used today to colour Hebron glass. Instead of sand, the raw material used to make Hebron glass today is primarily recycled glass, which is gathered from local houses, brought to the factory to be smashed, and re-melted.