Is combining gems worthwhile?

The upper tier gems are very desirable items to obtain for top tier players.

Is it worth it to combine gems in the lower tiers to build up to them (obviously upper tier gems must be combined or purchased)?

Is there a certain break point where it isn't worthwhile to combine gems below that quality?

Worded differently, what price must the auction house demand for a gem before it is not worth combining them yourself?

As stated here, the new costs in the 1.0.3 patch deployed on June 19 are:

Quality       Previous Cost                      New Cost
Flawed        3 Chipped + 500 gold               2 Chipped + 10 gold
Normal        3 Flawed + 750 gold                2 Flawed + 25 gold
Flawless      3 Normal + 1250 gold               2 Normal + 40 gold
Perfect       3 Flawless + 2000 gold + 1 Page    2 Flawless + 55 gold + 1 Page
Radiant       3 Perfect + 3500 gold + 2 Pages    2 Perfect + 70 gold + 2 Pages
Square        3 Radiant + 7500 gold + 1 Tome     2 Radiant + 85 gold + 1 Tome
Flawless Sq.  3 Square + 20,000 gold + 2 Tomes   2 square + 100 gold + 2 Tomes

For example, to upgrade from chipped to flawless square:

1 Flawless Square 
  = 2 square + 100 gold + 2 tomes
  = 2 * (2 Radiant + 85 gold + 1 tome) + 100 gold + 2 tomes
  = 4 * ( 2 Perfect + 70 gold + 2 pages ) + 270 gold + 4 tomes
  = 8 * ( 2 Flawless + 55 gold + 1 page ) + 550 gold + 8 pages + 4 tomes
  = 16 * ( 2 Normal + 40 gold ) + 990 gold + 16 pages + 4 tomes
  = 32 * ( 2 Flawed + 25 gold ) + 1630 gold + 16 pages + 4 tomes 
  = 64 * ( 2 Chipped + 10 gold ) + 2430 gold + 16 pages + 4 tomes  
  = 128 Chipped + 3070 gold + 16 pages + 4 tomes

Assume drop rates are going to remain unchanged and thus the prices of pages and tomes should be relatively stable (this assumption may be invalid, explain why if you disagree).

At what price for a flawless square does it become worth taking a DIY approach?

Solution 1:

THIS ANSWER IS UPDATED AS OF PATCH 2.0/REAPER OF SOULS

All previous answers assumed an environment where the Auction House was a possibility for gem procurement. This is no longer the case in patch 2.0, and in order to get gems above the "Imperial" level, you must pay Covetous Shen to combine gems, as well as provide a few materials beyond simply money and gems at the highest levels.

So, is it worth it to combine gems?

YES (for Marquise and up).

In Patch 2.0, it is possible for Marquise gems to drop from level 61 and higher monsters. It is also possible for Imperial quality gems to drop from level 61 and higher monsters on Master difficulty and higher.

The gap between a Marquise gem and an Imperial gem is substantial, but gets even higher as you go further. Let's take an example of an Emerald placed in your chestpiece...

• Marquise: +62 Dexterity
• Imperial: +100 Dexterity
• Flawless Imperial: +160 Dexterity
• Royal: +220 Dexterity
• Flawless Royal: +280 Dexterity

So, given that you can achieve a boost of +180 to a particular stat by combining gems over what you can get just from drops, it is absolutely worth it.

Below Marquise you will have to spend to upgrade Covetous Shen and then further spend to update the gems. If you can afford it, go ahead. More likely by the time you go through the effort you will either outgrow the piece of equipment or drop higher level gems. It's really not worth the effort though.

Solution 2:

No.

This will vary wildly by current market conditions, but as of now, the answer is no. Gems below Flawless Square (the highest level that drops) are dirt cheap on the AH - often cheaper than the fee to combine three gems of the previous tier - to say nothing of the value of the gems themselves!

Over the course of the past 12 hours, I've been periodically checking the AH prices for an order of 10 gems of each type, in every quality from Chipped through Perfect Square, noting both the price I was being offered, and the "Average Last 10 Trades". I did a bunch of rounding and averaging to get these thoroughly unscientific prices for each Gem Quality:

Gem Quality             Amethyst     Emerald     Topaz     Ruby
#1: Chipped:            115          180         125       200
#2: Flawed:             45           50          100       125
#3: Normal:             50           100         60        175
#4: Flawless:           40           125         80        225
#5: Perfect:            185          225         150       725
#6: Radiant:            250          350         250       850
#7: Square:             450          900         850       2000
#8: Flawless Square:    5000         7000        6500      9250
#9: Pefect Square:      75000        80000       70000     85000

While the prices you see may vary, the point is that at the moment, the market for gems below the Perfect Square level is very much a Buyers Market - crafting is a waste of gold, and of precious Jewelers Pages and Tomes.

Solution 3:

Is just a matter of math. I did some quick yesterday and it's not worth for:

• Rank 1 Chipped: n/a
• Rank 2 Flawed: 500 gold
• Rank 3 Regular: 750 gold
• Rank 4 Flawless: 1,250 gold
• Rank 5 Perfect: 2,000 gold and 1 Page of Jewelcrafting
• Rank 6 Radiant: 3,500 gold and 2 Pages of Jewelcrafting

You get lot's of those in hell/inferno

I even could say to avoid

• Rank 7 Square: 7,500 gold 1 Tome of Jewelcrafting
• Rank 8 Flawless Square: 20,000 gold and 2 Tomes of Jewelcrafting

Because they all can drop.

Focus your gold on the ones you CAN'T drop.

• 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

Source How much does it cost to combine a gem?

Solution 4:

It is absolutely worth it ¹

¹ But only from flawless squares and up.

The total cost of crafting to go from a flawless gem to a star gem is 500k gold + cost of supplies.

The cost to buy a Star amethyst, topaz, etc are usually 600k+ (700k+ for a star emerald).

Add this to the fact that flawless squares and tomes of secrets drop on inferno difficulty (i.e. effectively free), its cheaper to find and craft your own that to buy from the AH.

Even if you buy materials from the AH, the 27 flawless squares and the amount of tomes of secrets costs less than the extra 100-200k you'll have to pay to purchase star gem outright.

Now, whether or not you earn a profit if you choose to sell your star gem is a different issue since you'll take a 15% hit from the transaction fees, but if you need a star gem to use its definitely cheaper to craft your own (assuming your jeweler is already upgraded to the max).

Solution 5:

Edit: earlier answer was based on AH price from a couple of days ago, just went throug the price for Amethyst and updated the answer.

With the changes in 1.0.3 it will be worth while combining gems form Flawless Square and up (based on current EU SC AH prices).

Anything lower will not be worth it due to the price of Page/Tome of Jewelcrafting being higher than the AH price of gem created with them.

Unless blizzard buffs the drop rate of Page/Tome of Jewelcrafting(there by lowering the price) chances are that upgrades will always start at Flawless Square or Square gem if you happen to find some cheap tomes.