The right kind of sand for making glass isn't found everywhere. In the UK, we have a particular problem that the only glass-suitable sand we have is not suitable for making clear glass, so we can only make coloured glass. All our clear glass is imported, mostly from France. However, most local recycling centres only have a "mixed colours" glass bin, so we can't even make our own recycled clear glass. And That's Why We Can't Have Nice Things (tm).