Synthetic gems are man-made gems created to imitate the look and feel of natural gems. The two crossword solutions for the term 'synthetic gem' are boule (5 letters) and rutile (6 letters). Boule is a type of synthetic gemstone that is made from a mixture of quartz and other minerals, while rutile is a synthetic gemstone made from titanium dioxide. Both of these synthetic gemstones are used in jewelry and other decorative items.