What are those Crystals on your Wine Cork?

Have you come across crystals on your wine bottle or cork?  Is that a problem? Not at all.  Wine diamonds, as they’re sometimes called, are tartrates that are formed when potassium or calcium and tartaric acid bind together to form crystals. Both are naturally occurring products of wine grapes and you may know potassium bitartrate as cream of tartar. They are little gems that are often a result of handcrafted wine.