Sand crystal

[semisweetchk]

My mother-in-law owns some old glassware that she insists is 'sand crystal'. It is very delicate and makes a ringing sound like lead crystal. Has anyone ever heard of this type of glassware? How is 'sand crystal' made?

[compo]

There is a very fine crystal that is used to make 'ringing' bowls etc, but I've never heard of 'sand crystal'. Sand is obviously a key component of any crystal or glass. Could it be some confusion about the proportion of sand used to make the crystal?