If you get it all the time and you get it again soon, at least before you get the Unicorn Horn then it was not a bad idea. but it is a gamble selling a gem that you still need. That is why ever since Doug appeared in
WW I am keeping all my gems...except for today since I found the Gem of the Day and did have that emerald already. I have been trying to get that crown for 7 months and STILL need to find two more gems, the cat's eye glint and ocean sapphire.
I really wish we could trade gems with other players! for some reason each account is different on what gems are easier to find than others. I am sure some other people here have found like 100 of those two gems I need!