谢谢找到了

The lost gem is found by following the storyline

你好 那你知道那颗丢失的宝石在哪里？Hello, do you know where the lost gem is?

You are awesome for doing this. Doing it ''in game' is hugely painful.

Very usefull, looking at Constellation through the inventory screen is a pain. Thanks. :)

I finally retraced my steps and found the Salmon. The reason the geode doesn't appear on the map of the Forest of Inshriach is that it's in The Glade of Mathan region. That region had 4 corruption sites and the Geode in a different direction, and a Fairy Golf puzzle that allowed one to kick a ladder down and slide back to the main area of Forest of Inshriach.

Now you're asking... obviously didn't need to look again once I'd made the list, so I don't remember. It may be that one of the stars in the figure takes you nearby the geode. You know you can light one at a time and go to it, and then back to Skyhenge?

Where in the Forest of Inshriach do I find the Salmon constellation? I only have 11 "Geodes" appearing on my map, and the missing one is the Salmon.

I can just enter it on the Skyhenge based on your images here, but I'd like to know where the appropriate Geode is to acquire it for myself.