This is a 13 mm x 6.5 mm Swarovski crystal briolette in silver shade, which is almost clear, but has a hint of color.
Side drilled at the top.
Works well with an ice pick bail to make either dangle earrings or a pendant.
Just insert the points of the ice pick bail on either side of the drilled hole and pinch closed. No glue is required.
Beautiful and inexpensive!