In 50 you will get 2 to 3 pcs and in to 100 Gram  3 to 4,5 pcs of Pyrite
 
Pyrite- has long been valued as a strong protection stone that shields the wearer from negative energy as well as environmental pollutants. Thus, this stone helps promote physical well-being as well. Stimulating the second and third chakras, pyrite enhances strength of mind and willpower.
Pyrite is a powerful protection stone which shields and protects against all forms of negative vibrations and/or energy, working on the physical, etheric, and emotional levels. Pyrite inspires the universal energies to activate the nourishing energies of the body.