Crystals are pure forms of minerals made out of atoms. The atoms are arranged in patterns unlike most rocks. Most crystals form in the mantle and are brought up by volcanos. A organic gem is a gem formed by living things. For example pearls and amber are organic gems. Most mineral gems are underground so to get them people have to dig a hole that goes underground and mine for them by hand. When gems are formed they look dull dark rough edges etc. So lapidaries (gem cutters) cut polish and hide flaws so they look like what you see in the store.