­Doubling Cube? this is much more powerful. 10 mana with 5 lands. play 2 and now you have 20 mana.

cube is a bit weak. i think 3 to cast and 2 to activate is fair.

It's like doubling cube - but this caps out at +5 mana, where the doubling cube lets you dream of ridiculous power.

the cube doesn't overtake this until you're at 11 mana though; unless you need a particular colour of mana in quantity.

So yeah, this is a fairly scary. But it is a 5 cost. A small activation cost would be appropriate, I think - or bump it to 7 mana or so.

ya i misunderstood the card. better cards to compare are

• Astral Cornucopia , 6 for 2 mana of one color
• Gilded Lotus, 5 for 3 mana of one color
• Thran Dynamo, 4 for 3 mana colorless

Difference with Gem is you have to use the mana on the same turn.