1.Place 2 shallow metal containers in the freezer to chill. Combine rockmelon half the water and half the sugar in a saucepan over low heat. Cook, stirring, for 2-3 minutes, or until sugar dissolves.
2.Increase heat to medium. Bring to boil. Cook for 5 minutes or until syrup thickens. Set aside for 5 minutes to cool
3.Combine the raspberries remaining water and remaining sugar in a clean saucepan over low heat. Cook, stirring, for 2 minutes or until sugar dissolves. Increase heat to medium. Bring to the boil. Cook for 5 – 7 minutes or until syrup thickens. Set aside for 5 minutes to cool
4.Place rockmelon mixture in the bowl of a food processor and process until smooth. Strain through a fine sieve into a metal container. Cover with foil. Place in the freezer for 2 hours or until almost set. Repeat with raspberry mixture.
5.Use a metal spoon to roughly break up the rockmelon mixture. Transfer to the bowl of a food processor. Add half the egg white and process until mixture is smooth. Return to the container. Cover with foil and place in the freezer for 4-6 hours or until firm. Repeat with the raspberry mixture and remaining egg white.
6.Scoop the rockmelon, raspberry gelati into serving bowls. Serve immediately.