History of Phaseglass Refraction

Phaseglass Refraction is a common destination material on Kepler, introduced with Destiny 2: The Edge of Fate.

Where to find it

Crystal shards stick out of rock in The Gorge (unlocked after the first two Strangelets in the campaign, per Game Rant), in the Assimilated Easement and in The Stellar Sink (per ProGameTalk). Defeating the boss Cyclops Rampant, Conductor's Chosen is reported to drop 7.

Uses

It is traded at the Altar of Relativity for focused decoding of Kepler gear. The required material rotates daily, so players stockpile all Kepler materials, and Fated Ciphers are needed too.

Notes

Sources disagree on which areas hold it (The Gorge versus Assimilated Easement and Stellar Sink); likely all have it.