This set of four opaque red Christensen Agate glass marbles, measuring 13-15mm in size, is a great addition to any marble collection. These machine-made marbles date back to pre-1970s and are perfect for collectors who appreciate vintage style. The brand, Christensen Agate, is well-known for producing high-quality marbles and this set is no exception.

In addition to being a great addition to any collection, these marbles are also perfect for playing games or using in art projects. Their vibrant red color and unique texture make them stand out from other marbles. Don't miss out on the opportunity to add these rare gems to your collection.