Momme Weight:Because silk is such a fine fabric,it is generally measured by “momme weight” instead of thread count.Momme(pronounced “mummy”)is a unit of weight used to measure and describe silk fabrics,usually expressed in momme weight(m/m).The higher the momme,the heavier the fabric.GSM refers to grams per square meter of fabric.It is the major computation unit for fabric texture. 1m/m=4.3g. Silk under 19 momme (10 m/m,12m/m,14m/m,16m/m) is considered lightweight, 19 momme is considered mediumweight and anything above(22 m/m, 25 m/m, 30 m/m) that is considered heavyweight,You can calculate that if a 16 m/m silk charmeuse sells for $30.00 it would stand to reason that a 30m/m would be more expensive and so on.