The Gupta script, which is also known as the Gupta Brahmi Script or the Late Brahmi Script, was used for writing Sanskrit in the Gupta Empire, which existed from about 320 to 550 AD. It developed from the Ashokan Brahmi script, and developed into the Devanagari, Sharada and Siddham scripts
Gupta inscriptions have been found mainly on iron or stone pillars, and on numerous gold coins from the Gupta Dynasty.
Information about the Gupta script
http://en.wikipedia.org/wiki/Gupta_script
http://www.ancientscripts.com/gupta.html
http://www.indianetzone.com/11/gupta_script.htm
The Shivlee Collection of coins from the Gupta Dynasty
http://www.shivlee.com/theshivleecollection.html
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