As seen and available at the American Museum of Natural History, the New York Hall of Science, and the Oregon Museum of Science and Industry (OMSI)
The Public Lab Foldable Mini-Spectrometer folds up in minutes to transform your smartphone into a compact, simple, experimental tool -- a visible/near-infrared spectrometer, also known as a spectroscope or spectrophotometer.
This kit comes die-cut from thick, light-blocking black card stock and includes a DVD (used as a diffraction grating), a custom fit collimation slit, along with complete instructions for assembly (and downloadable design files), attachment to your phone or webcam, and calibration to take and share accurate spectra through Spectral Workbench. Just add glue or tape!
For a more rigid, robust tool, try the Desktop Spectrometry Kit, which is made of more sturdy construction and is designed to last.