The term 'Deep Blue Gem' is a combination of two words, 'SAPPHIRE' and 'Deep Blue'. SAPPHIRE is a precious gemstone that is typically blue in color. It is the second-hardest natural mineral after diamond and is often used in jewelry. The term 'Deep Blue' refers to a very dark shade of blue, which is often associated with the SAPPHIRE gemstone. Together, the two words form the phrase 'Deep Blue Gem', which is often used to describe a particularly beautiful and valuable SAPPHIRE.