20 Ticks is quite a bit of debuff time for as cheap as Gleam Sand is. I might look into a rebalance, but there's plenty of powerful items.
As for the Vigor Crystal, I can see it maybe being useful around the time you get it; the Great Vigor Crystal and Ring of Reprisal are roughly vailable around the same time, though they do compete for a slot. I'll look into giving HP a bit more use.