Silk:Silk is a natural protein fiber, produced by insects to form their cocoons. Silk can be produced by a number of different insects, but the most commonly used is silk from the mulberry silkworm. The fiber produced by these insects is harvested, unwound, and twisted together to form yarn, which can beused to make fabric. 

A term you're sure to come across when shopping for the best bed sheets is 'thread count'. The thread count refers to the number of horizontal and vertical threads per square inch of fabric, and higher thread counts often indicate softer high-end sheets. However, there is a happy medium at around 400-600 thread count that will give you a good balance between quality and price.

There are different varieties of cotton, as well as different quality levels. Two of the highest quality cottons are Egyptian and Pima/Supima cotton.Egyptian cottonis grown in Egypt, as the name suggests. Pima cotton is grown in the United States, although you might often see it referred to as “Supima,” as well. This is a portmanteau of “superior pima” and is a registered trademark of the Supima trade association, which promotes Pima cotton.