The two most common technologies are X-ray Fluorescence (XRF) and Ultrasonic Testing. XRF analyzers are the industry standard for non-destructive testing, providing a full elemental breakdown (e.g., identifying copper or nickel content) in seconds. Ultrasonic testers are better for detecting tungsten or lead cores inside thick silver bars. For B2B buyers, XRF spectrometers are highly recommended for their high precision (up to 0.01% accuracy) and ability to distinguish between silver plating and solid sterling silver.