Pearl (Steven Universe) projects a holographic butterfly.
 With X-rays it is possible to see the growth rings of the pearl, where the layers of calcium carbonate are separated by thin layers of conchiolin
 Another example is the conch pearl (sometimes referred to simply as the 'pink pearl'), which is found very rarely growing between the mantle and the shell of the queen conch or pink conch, Strombus gigas, a large sea snail or marine gastropod from the Caribbean Sea

