You need to use the ImportXML() function, which needs;
- Data Source (API), like http://evemarketer.com’s API.
- SystemID, Jita = 30000142
- TypeID of the item you want price data for, the minerals have typeIDs of 34 . . 40 (not including Morphite)
- Tritanium = 34
- Pyerite = 35
- Mexallon = 36
- Isogen = 37
- Nocxium = 38
- Zydrine = 39
- Megacyte = 40
- parameter for the Sell (min/max), Buy (min/max) or Avg.
You can read about evemarketer’s API here