In Which Hand and finger should I be wearing my Gemstones?

In Hinduism, Ardhanari or Ardhanarishvara (Sanskrit: अर्धनारीश्वर, Ardhanārīśvara), is an androgynous deity composed of Shiva and his consort Shakti, representing the synthesis of masculine and feminine energies. The Ardhanari form also illustrates how the female principle of God, Shakti, is inseparable from the male principle of God, Shiva. Ardhanari in iconography is depicted as half-male and half-female, split down the middle. The masculine part is the right side and the feminine part is the left side. Full expression of both these halves leads to complete self realization.
In General, all shastras- sacred texts have the unanimous view that Gents should wear the Gemstones in the right hand and Ladies should wear the Gemstones in the left hand. This is the thumb rule that gives good results.