The stone measures approx. 1/2" x 3/4" and was cut from the top of a green / aqua EC&M (CD 123). Gemcutters like working with these because the glass is much harder, cuts cleaner, and polishes better than ordinary glass. It really sparkles due to the many facets and the color and clarity of the glass. Great conversation piece - when asked what kind of stone is that, my wife tells people it's cut from a 120 year old telegraph insulator.