So glimmer is the money for the regular game. Helps you buy gear from npc, engrams and gear from weakest to strongest go from White Green, Blue, Purple, Yellow.
Then you have legendary shards. You get those from breaking down legendary equipment (purple) and exotic equipment (yellow) you can use those purple shards to buy from xur in the wild and to infuse gear that is stronger into legendary gear you prefer.
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Eph: 2:8