Transparent gem is a term used to describe a type of gemstone that is transparent or semi-transparent. Four examples of transparent gems are SAPPHIRE, BERYL, ZIRCON, and TOPAZ. SAPPHIRE is an 8 letter gemstone that is typically blue in color and is the second hardest natural mineral. BERYL is a 5 letter gemstone that can range in color from yellow to green to blue. ZIRCON is a 6 letter gemstone that is usually yellow, orange, red, brown, or green. TOPAZ is a 5 letter gemstone that is usually yellow, orange, or pink.