This recipe gels without added pectin. It relies completely on sugar and the natural pectin in the fruit and lemon for gelling. It can be used for peaches, too - and here is a bigger portion that will make 3 1/2 pints.
4 lbs unpeeled stone fruit (10 cups pitted and cut); peaches, nectarines, plums, apricots, or cherries
5 cups sugar
1 lemon, juice and zest