Green Crystals is a color-led catalogue path rather than a single-material family. Recorded material labels include Fluorite, Agate, Jasper, and Moss Agate, while the shape mix includes tumbled stones, towers, bracelets, and chips. Holding the color category constant makes both material and form variation visible.
Compare the material labels first—Fluorite, Agate, Jasper, and Moss Agate—then narrow the same color path by tumbled stones, towers, bracelets, and chips. Keeping those two filters separate avoids treating a shared color as proof of shared material or form.