Talk:Lighthouse Gem Monster/@comment-26286889-20150407083930/@comment-24391365-20150414221758

I very highly doubt it's Blue Diamond, such an important character wouldn't be so easily beaten, and more than likely that gem is on the gem home world with the other two diamonds.

Spinel could be the gem, though they come in a lot of colors and pure spinel is supposed to be clear. Maybe the fact it's not clear could indicate it's corruption.

More than likely it could be iolite since it was used by mariners as a compass like you said which goes with the lighthouse theme. I also read that it helps to stimulate memories, which is what it did in the basement when it showed the scene between Larz and Ronaldo in the past.