Historically the tallet was most commonly made of wool or linen, and to this day in many orthodox Ashkenazi and Eastern Sephardi communities, wool remains the fabric of choice, mainly due to an opinion that only these two materials fulfill the original Torah command (others being only a rabbinical addition).
However, in Western Sephardi and Italian communities with access to the silk route luxuriant, lightweight silk tallets became the tradition, as a way of honouring and beautifying the mitzvah.
These silk tallets were often personalized for their owners with elaborately decorated squares at each corner, emphasizing the four fringes.