Sphalerite in Quartz
A faceted colorless Quartz with a few dark red Sphalerite crystals inside. It weighs 14 carats and comes from a find about 5 years ago in Goias, Brazil.
There is an article about this at the Journal of Gemmology, volume 35, No 1, 2016.
2.1 x 1.1 x 0.6 cm