Jewels and gems are important spiritual and religious symbols.  In general, they represent light, heat and the sun, especially the spiritual sun.  The cutting of rough stones into gems is symbolic of or jouney to spiritual enlightenment where the rough, materialistic, egotistic person is "cut" into a spiritually advanced one.  In Buddhism, jewels represent wisdom.  Dreaming about jewels usually symbolizes that you are heading for spiritual growth, or should be depending on the details of the dream.  
    In one dream I had not long after joining the International Community of Christ, I was walking along a path through woods on a bright, sunny morning.  I came to an open area where the sun was shining down on the rocks covering the path.  I noticed that one of the rocks was very shiny so I picked it up and turned it over.  It was full of gems, or crystals, a piece of a geode.  I then started picking up other rocks and turning them over and found that many of them were geodes full of crystals and gems of many types and colors.  This dream, along with others, helped convince me that I was following the right path.  
    In the Bible, the throne of God is described as being covered with gems of many types.  Arron, the high priest and brother of Moses wore a brestplate with gemstones.  The Essenes carried gemstones with them including the healing "essen" stones from which they get the name "Essene".  Even cavemen picked up shiny stones and wore them. 
    There are many more symbolic meanings of specific gems, jewels and crystals, but I have covered most of those in posts about those stones.