Thanks Purpz, this answers a lot of questions I had in regards to island level. Do you know why blocks like quartz and beds, which are significantly rarer than other blocks, fall into the same category as netherrack?
No, I don't know the reasoning behind the point system. Personally, I'd much rather build with quartz than netherrack and agree it should be worth more. The values are customizable, but as far as I know, haven't been customized on either Skyblock or Islands. Would be kind of fun to suddenly make netherrack worth 250 points and diamonds worth 1. Or maybe that is just my bad sense of humor
Huh, I would think that an emerald block would give more levels than a diamond block, seeing as emeralds are rarer, and that diamonds can be purchased in the shop.
Actually since the points are divided by 3 like @Purple4me said, the island level would go up by 3, but the block is technically worth 300 points, just to clarify.