Yes, there are apps available that claim to help test diamonds, but their effectiveness can vary widely. Some apps utilize your smartphone's camera and algorithms to analyze certain visual aspects of a diamond, such as its brilliance or light refraction properties. While these apps may provide some insights into a diamond's quality or characteristics based on visual examination alone, it is important to note that they cannot definitively confirm whether a diamond is genuine or synthetic. Professional jewelers rely on precise measurements and thorough examinations beyond what an app alone can offer for reliable authenticity assessments. Therefore, it is wise not to solely rely on such apps when determining the authenticity of diamonds.