Major Fractaline Harvest is a new resource in Destiny 2 that comes during the Season of Dawn update. You need it to fuel the Obelisks now scattered throughout the solar system attuned to Osiris’ Sundial on Mercury. By collecting Major Factaline Harvest, and using it to increase the Resonance Rank of the Obelisks, you can access Obelisk enhancements and additional rewards.
To activate the Obelisks, you first need to work through the A Matter of Time quest, which you can start by visiting Ikora in the Tower. To get Major Fractaline Harvest, you need to complete the Obelisk on the Tangled Shore. Once this happens, you earn some Major Fractaline Harvest.
To earn more, you will need to complete Obelisk Bounties, or Sundial runs on Mercury. Each Obelisk starts by giving you two Bounties a week, that you can take up to seven days to complete. Upon completion, they reward you with some of the resources. You can then redeem the resource at the Obelisk to upgrade it.
This resource works the same way as Tokens from Iron Banner or any of the playable areas. You visit the Obelisk and interact with it to bring up the Obelisk menu, then click the symbol to redeem the resources. When you fill the bar, you will receive a Resonance Rank Reward. You will also be able to upgrade the Obelisk using Glimmer and purchase Timelost Weapon Bounties to complete.
The different Obelisks can be linked to the Sundial on Mercury and will influence the rewards that can drop from completing Sundial Runs for Osiris.