Kohdok's Great Gathering Guide!
Gathering is an important part of Lightseekers. All over the map are small features that can be harvested for crafting items and xp, with each kind of harvestable item giving different yields and EXP. It can be a little hard to suss out what items can be gathered, which is why this guide will exist. There are a variety of items which can be harvested and each one belongs to a different order. The exp yield from all of these items can be buffed by scanning the appropriate Tribute cards that give a boost to each Order.
In general, items which can be gathered stand out via a small particle effect at the base. Tapping that spot will shift the Lightseeker into a gathering animation, where the Lightseeker, along with equipped weapons and pets, will gain exp until the item is fully gathered and disappears. Gathering is actually a very effective and reliable way of gathering exp and can be simple to do while avoiding combat.
NOTE: As of the 05/31/17 update, the particle effect surrounding Gatherable items has been enlarged to make them easier to spot.
As you gather items, your gathering skills will also gain EXP. Levelling up your gathering skills will allow your Lightseeker to harvest rarer and more delicate gathering spots to gain rarer crafting items and earn even more exp. If you see a rare Gather Spot, but aren't a high enough level to harvest from it, don't worry! The spot will stick around until you can reach it(with the exception of Extraction, as their spawn points are constantly shifting.)
You can find your Lightseeker's Gathering stats by going to the bag, then the Hero screen, clicking "Stats" and then scrolling down. As you can see, some stats are easier to level than others.
NOTE: As of the 05/31/17 update, your gathering skills have been given progress bars to see how close you are to your next level.
Gathering Spots Guide
The key here I use is simple:
Gathering Skill - Order - Harvested Item
Extraction - Astral - Stardust
Extraction is an interesting case in that they give by far the most EXP of any gatherable item, but have no set area where they appear, instead spawning randomly in areas that are thick with dangerous enemies, meaning you will have to roam the map to find them. There is a high risk/reward factor to Extracting, but it is always worth it.
Siphoning - Dread - Essence
These dark crystals are all over the place, usually found in the furthest corners of the world, be it a natural environment or a Kreebal camp. They provide average exp.
Mining - Mountain - Ore
Mining ores tend to appear in rocky areas or areas with lava, though they can appear in fields, as well. Ores provide very low EXP.
Herbalism - Nature - Plants
Plants are everywhere, usually resembling a coiled plant or a green flower. They give average exp.
Cloud Harvesting - Storm - Clouds
Clouds appear sporadically, usually near villages, but often alone, making them somewhat rare.
Salvaging - Tech - Scraps
These little piles of junk are usually found in Umbron camps and give average exp.
Gathering Area Maps
Ashwood Map by @David K? (Keep in mind the yellow Extraction points will not always be there and will usually spawn in only one place.
And that is all for now. I will be updating this guide as I get more pictures of the higher level items, but until then, happy hunting!
EDITS: Added Ashwood map, edited for more coverage. Added Salvage LV10 pic. Added Extraction LV25 pic. Added Siphoning LV25 pic. Added Mining LV10 pic.