Glass is Endlessly Recyclable
Unlike fiber-based (e.g. paper) & petroleum-based (e.g. plastics) products, which degrade to various extents with each trip through the recycling process, glass-based products (e.g. bottles) are "endlessly" recyclable, meaning they do not suffer statistically significant losses in quality or purity when recycled.
Glass bottles and aluminum cans are two of just a small handful of perpetually-recyclable container types.