These mini knife carvings come in a variety of shapes and sizes as well as stone types.
The Amazonite knife is ~4cm and 4g. The Golden Healer (clear quartz with yellow streak) knife is ~5.5cm and 9g. The Que Sera knife (also called Llanite or Rhyolite) is ~5.8cm and 13g. White Quartz knife is ~6cm and 14g. The Flame Quartz (pale quartz with red streak) knife is ~6.5cm and 17g. The Amethyst knives are ~6-6.5cm and 17g.
Where there is more than one of a stone type, yours will be intuitively chosen for you.