The term 'Pale Gemstone' can be summarized by the crossword solution of 'OPAL'. OPAL is a type of gemstone that is known for its unique play of color, which is caused by the diffraction of light through its micro-structure. It is a hydrated amorphous form of silica, and is usually found in sedimentary rocks. OPAL is often characterized by its milky white or pale color, making it a popular choice for jewelry.