During the excavations just outside of the Long Barrack, fragments of glass were recovered. These glass fragments are dark olive green in color, often referred to as black because the color is so dense that light cannot pass through.
Often, the dark olive glass fragments come from wine bottles, and the thickest fragments can represent the kick-up located at the bottom of the bottle.
Dark olive glass appears to have reduced in popularity around the 19th century. It has been found at many of the other Spanish Colonial sites in Texas. These vessels are usually hand blown.