Rectangular Silk:

7.6cm deep by 3.8cm wide

As with many of these woven rectangles, there is no woven name. It is assumed to be of STEVENS manufacture however, although it does not have the same broad characteristics of the other rectangular silks. There would ordinarily be a patterned border round the outside of the silk, and this is missing.
The image above is of the rectangle woven silk mounted in a modern card frame. The usual STEVENS silk rectangles would have had a fringe at top and bottom, although it is unlikely the image above had such a fringe.