Henrietta cloth is a type of fine woolen fabric which was often used to make women's dresses and gowns until the early 20th century, when it was supplanted by other materials, including synthetics. You may occasionally see Henrietta referenced in Victorian mourning guides, because it was deemed to be an appropriately somber fabric choice for recently widowed women, and it was also worn on more festive occasions, like winter weddings. As a general rule, Henrietta cloth tended to be rather expensive, restricting its ownership to the upper classes.
This fabric is named for Henrietta Maria, the French consort of Charles I of England, who lived during the 1600s. The fabric is typically made in a twill weave, which means that it has subtle parallel diagonal ribs. This weave is particularly sturdy, and it can be used to create a variety of effects in fabric, since it is difficult to pull out of shape. Classic Henrietta cloth is black, although it can come in a variety of colors.
Most typically, Henrietta cloth has a faint luster to it, which may be enhanced by special treatment of the fabric. In order to be considered true Henrietta cloth, the fabric must be made from wool, which is typically finely combed to achieve the desired weight and luster. As a result of the fine combing and special treatment, the wool typically turns out extremely soft, making Henrietta cloth almost like cashmere, a far cry from the scratchy, coarse texture many people associate with wool.
This fabric is not generally deemed to be appropriate for men, and it was sometimes not recommended for older women, as well, because it could be deemed too flashy with its extreme softness and luster. Many widows wore Henrietta cloth because it could be made to look very stylish while remaining plain, and the distinctive look and drape of the fabric suggested that a widow was both wealthy and stylish, even in her grief.
It can be a bit of a challenge to find this material these days. It is certainly possible to find vintage dresses and gowns made from Henrietta cloth, and it is sometimes possible to obtain old bolts of material, which should be inspected carefully for signs of decay. Most fabric manufacturers do not manufacture this particular style of wool today, however; you may want to ask a fabric specialty store if you have a specific need for Henrietta cloth in particular.