Indus Valley Script

     The Indus Valley script originated in the late 2nd millenium b.c. It was used to write on clay seals. It has in the range of 400 symbols and is probably a logophonetic script in which the symbols may mean what they symbolize, or words that are similar in sound. The texts are largely undeciphered.
     The image on the stamp is a picture of a seal itself, not of the impression made the seal makes.

Kharoshthi

     Kharoshthi is the oldest Indian script apart from the Indus Valley script. It is probably based on Aramaic. It appeared in northern Pakistan and eastern Afghanistan between 500 and 300 b.c. In Kharoshthi vowels are indicated through systematic modifications to the consonant symbols.

Hindi

     Hindi, the official language of India, uses the Devanagari alphabet, which  has 33 consonants and 11 vowels. It was orginally used to write Sanskrit, and now is also used to write Marathi, Nepali, and several Indian dialects.