Also called Chhoti Elaichi (Small Cardamom) or Hari Elaichi (Green Cardamom), or true cardamom, it is another notable member of the ginger family Zingiberaceae. It is a cool spice with a distinctly minty aroma and has medicinal properties.
Choose the ones with dark, oily-looking seeds for the most potent burst of flavour, as the one on the right side in the picture below.
The left-side one would have all the flavour of cardboard.
Caveat Emptor: This is because sometimes the flavours are harvested (distilled) and the spices then sold.
Wikipedia link to Cardamom.