Glimmer

Glimmer is a type of currency. It can be used to upgrade weapons, and buy items.

Overview
Majors and Ultras (enemies with yellow health bars) such as Riksis, Devil Archon drop Glimmer when killed. Normal enemies only drop Glimmer if the player has used Ether Seeds, Black Wax Idol, Blue Polyphage, or Resupply Codes, or a Legendary Ghost. Glimmer is also gained by disassembling items or finding some in loot chests. Another source of Glimmer comes from selling House Banners, Silken Codexes, Axiomatic Beads and Network Keys to the Cryptarchs for two hundred fifty Glimmer each.

As of Shadowkeep Glimmer drops on almost every enemy kill. Shadow Thralls drop Glimmer on death in patrol zones, but leave no Glimmer in The Shattered Throne.

In Destiny, Glimmer is capped at 25,000; one way to circumvent the cap is to stockpile the aforementioned items and sell them to the Cryptarchs when needed. In Destiny 2, Glimmer is capped at 250,000.

Trivia

 * Glimmer is apparently buried deep within the earth and can be extracted from the ground, as the Fallen will attempt to do so with portable Glimmer Drills in some Public Events. Or it is possible glimmer was stored in vaults and other secure locations before the Collapse and now they try and excavate the old vaults to gain access to the glimmer within.
 * According to the Grimoire card, Glimmer is a "programmable matter" which can be transmuted into nearly anything. This function is not displayed in-game, as the only shape Glimmer takes is small cubes.

List of appearances

 * Destiny
 * Destiny 2