These are Swarovski crystal briolettes in a tanzanite blue-violet color.
Side drilled at the top.
These work well with ice pick bails to make dangle earrings and pendants.
Just insert the points of the ice pick bail on either side of the drilled hole and pinch closed. No glue is required.
Briolettes measure 9 mm x 5 mm. Sold as pairs.
Beautiful and inexpensive!