Momme (mm) is a unit used to measure the quality and density of silk fabrics. One Momme equals 4.340 grams per square meter. The higher the momme weight, the better? Yes and no. It depends. Typically, the higher the momme weight, the more durable the weave, the more luxurious the fabric is, the more suitable it is for heavy-duty use, and the longer the shelf-life. Generally, all silks can be washed, and the heavier ones can be washed repeatedly. The heavier the silk, the more opaque it becomes. This can vary even between the same kind of silk. For example, lightweight Charmeuse is translucent when used in clothing, but 30-momme CCharmeuse is opaque. Therefore, it does not mean that you must always buy silk products with higher momme weight. For instance, it would be too heavy to put on 25mm silk sleepwear for the night, but 19mm silk sleepwear is not that durable, though. In a word, it is a question of making proper choices according to your own needs. The usual range of momme weight for different weaves of silk are: Gauze—3 to 5 mm Organza-4 to 6 mm Chiffon-6 to 8 mm (can be made in double thickness, i.e. 12 to 16 mm) Habotai—12 to 16 mm Crepe de Chine-12 to 16 mm Charmeuse-12 to 30 mm Raw silk-35 to 40 mm (heavier silk appear more "wooly") What is thread count? Thread count or threads per inch (TPI) measures the coarseness or fineness of certain fabrics, most notably cotton. While it is not the definitive measurement of the quality of silk fabrics, it is suitable for reference when you purchase silk online. It is measured by counting the number of threads contained in one square inch of fabric or one square centimeter, including both the length (warp) and width (weft) threads. The thread count is the number of lines counted along two sides (up and across) of the square inch, added together.