Be sure that the sugar is completely dissolved into the solution otherwise it could easily crystallize. You're making gooseberry Jam - not candy. Once you are absolutely certain the sugar has fully dissolved turn the heat up and boil vigorously for another 10 minutes.
Do a Jell Test - if it passes pour it into your sterilized jars label and seal it - If not - return it to boiling for a tad longer.
Jell Test - Setting Point is reached when the boiling liquid begins to clot. There are various ways to check for setting.
1.} Dip a long wooden spoon into the pan and hold it up so you can see the liquid run off. If it starts to form flakes as it drops, setting point has been reached.
2.} Pour a spoonful of the hot mass on to a plate and refrigerate for 10-15 minutes.
Push the edges of the jam with your index finger, it is set when it all wrinkly and crinkly. Always test for setting point at the time the recipe suggests, if not set, continue to cook checking every 5 minutes. Don't overcook.