With a spectrometer you can reveal the composition of an object.
The SparkFun Triad Spectroscopy Sensor is a powerful optical inspection sensor also known as a spectrophotometer. Three AS7265x spectral sensors are combined alongside a visible, UV, and IR LEDs to illuminate and test various surfaces for light spectroscopy. The Triad is made up of three sensors; the AS72651, the AS72652, and the AS72653 and can detect the light from 410nm (UV) to 940nm (IR). In addition, 18 individual light frequencies can be measured with precision down to 28.6 nW/cm2 and accuracy of +/-12%.
The Triad Spectroscopy Sensor communicates over I2C by default or over 115200bps serial. SparkFun has written a fully formed Arduino library to access all the various features include taking readings and illuminating LEDs all over the Qwiic I2C interface. In addition, the Triad can be setup to communicate over serial. The serial interface uses an AT command set.
More information is available on the website of Sparkfun.