Clean the quinces and apples, peel them and remove their seeds. Put the cleaned quinces in slightly acidic water to avoid browning. Cut the fruits into small pieces, and meanwhile, put water and sugar in a large pot on the stove to make the sugar syrup.
When it has slightly thickened, add the chopped apples and quinces. Simultaneously, you can put the fruit peels to boil for 15 minutes in a little water. Strain the liquid into the fruit pieces and boil until the jam thickens.
Finally, add citric acid and geranium, if desired. While still warm, distribute the jam in dry warm jars, close and sterilize them for 10 minutes.