Quartz (rock crystal) faceted points. April birthstone.
Clear quartz points (rock crystal), that have been cut such that they stand securely on their own. The middle one has a delicate internal structure that looks a little like trapped bubbles. Rock crystal is a more recent British birthstone for April.
Left: 7/16 inch (1.1 cm) wide, 5/16 inch (0.8 cm) deep, 1 inch (2.5 cm) tall.