There are several types of silk charmeuse. Some of them may look exactly the same at first glance but upon thorough inspection, you can see the difference.
Crepe Back Silk Satin. The face of this gorgeous silk fabric is shiny while its crepe back fabric is ribbed with a soft pebble-like texture. The fabric is medium in weight and has a high sheen, similar to charmeuse, only heavier and more luxurious. Each side offers a distinctive look and can be mixed and matched within the same garment to create a visually interesting appearance. Silk crepe back satin feels simply divine and is milled from only the finest silk.
Stretch Silk Charmeuse has the same sheen and softness but with a 5% addition of spandex to make it a little stretchy and even more comfortable for clothing.
Sand washed Charmeuse has the shiny side abraded to tone down the sheen and make it more subtle, which makes it even more buttery soft than satin.
Having learned this, you should be able to distinguished the types of silk charmeuse and use it according to what fabric you need.