Set 2 small plates in the freezer. These will be used later to test consistency.
Place the raspberries, halved apricots, and white wine in a large, heavy-bottomed pot over medium heat. Bring mixture to a boil, cover, and reduce heat to low. Cook the raspberries and apricots until tender (timing will depend on how soft they are at the beginning).
Remove the lid and add the sugar, stirring to combine. Increase heat to medium and let the mixture violently bubble up. Eventually the bubbles will start to rise and with them a white foam. Skim off any foam that rises to the top. Once you've skimmed all foam, reduce heat to medium-low, and cook until the mixture thickens and reduces. Be sure to stir frequently to keep the bottom from burning.
To test the consistency of your jam, take one of the plates from the freezer, and spoon a small amount on the plate. Return the plate to the freezer, and wait 2 minutes. Push the chilled jam with your finger. If it starts to pile up on itself, it's done. If it seems too thin, cook the jam for 5 to 10 minutes more, and test again. This whole process took me about 35 minutes.
Once you've achieved the desired consistency, take the jam off the heat. Stir in lemon juice and St. Germain liqueur. Add additional lemon juice and liqueur to taste. I sprinkled in a bit more lemon juice and another splash of liqueur.
Transfer jam to a large, clean container (or several small containers), cover tightly, and let cool to room temperature. Store in the refrigerator for up to 1 year. The flavor will diminish as the months go on, so I'd recommend eating the jam sooner rather than later.