On the AH it seems like the cost to buy some of the gems outright is cheaper than it is to combine 3 lesser gems, but I don't have any to check. How much does it cost (in gold and materials) to combine gems between each quality level?
In case you were interested in the cumulative costs:
Rather than starting with a Chipped gem, here are cumulative costs starting with Flawless Squares (the highest rank gem that drops):
I've listed all of the costs below. Remember, that this is the cost in addition to the gems of the previous level.
The recipes below require 2 gems of the previous level
- Rank 1 Chipped: n/a
- Rank 2 Flawed: 10 gold
- Rank 3 Regular: 25 gold
- Rank 4 Flawless: 40 gold
- Rank 5 Perfect: 55 gold and 1 Page of Jewelcrafting
- Rank 6 Radiant: 70 gold and 2 Pages of Jewelcrafting
- Rank 7 Square: 80 gold 1 Tome of Jewelcrafting
- Rank 8 Flawless Square: 100 gold and 2 Tomes of Jewelcrafting
The gems below do not drop and must be crafted using 3 gems of the previous level
- Rank 9 Perfect Square: 30,000 gold and 3 Tomes of Secrets
- Rank 10 Radiant Square: 50,000 gold and 6 Tomes of Secrets
- Rank 11 Star: 80,000 gold and 9 Tomes of Secrets
- Rank 12 Flawless Star: 100,000 gold and 12 Tomes of Secrets
- Rank 13 Perfect Star: 200,000 gold and 15 Tomes of Secrets
- Rank 14 Radiant Star: 400,000 gold and 20 Tomes of Secrets
Thankfully, Gems in Diablo III are reusable, so you won't have to recreate Rank 14 gems every time you get a new socketed upgrade.
2Might want to add that flawless square is the highest possible drop, and you'll need 729 of those in total to get a Radiant Star. May 20, 2012 at 17:19
5@RavenDreamer Also, if you disenchant an item with a gem, it'll give your gem back.– MichelMay 21, 2012 at 17:02
1Stats fixed. Man, Rank 14 is expensive. May 21, 2012 at 18:48