Wowhead indicates by DEing Carnelian Spikes theres a 75% chance to get anywhere from 2-6 Greater Celestial Essence.
Let’s look at the maths….
So 75% chance means if I DE 40x only 30 are going to give me any Greater Celestial Essence.
There’s a Bonus to being in a lvl 25 Guild aka Bountiful Bags
I ended up with 88 Greater Celestial Essence so the drop rate was 88/30=2.93.
From my experience with this item my rate of 2.93 was a bit low, I obviously didn’t get many Bountiful Bags procs this time.
Now let’s look at the costs of this exercise.
I bought the Carnelian for 25g ea so 120x25=3000g
Jewlcrafter’s Setting 120x1.27 = 152g
So all up the mats cost me 3,152g
Greater Celestial Essence are going for 40g ea
88x40 = 3,520
Hypnotic Dust go for 60s ea
30*.6 = 18g
Total sales 3,538
Profit of around 386g not great but as part of the shuffle where we can benefit from economies of scale, this keeps our Enchanting mat costs down to maximise profit on sales.
The other alternative is to create 40x Inferno Rubys
Costs 120x Carnelian @25g ea = 3000g
120x Heartblossom @ 4g ea = 480
Total Costs 3,480g
Again we can expect to receive a bonus from Bountiful Bags.
Let’s say we got 1 extra in 10 crafts = 44 Inferno Rubys
44x 100g ea =4,400g
If Inferno Rubys fell to 88g then I could expect the approximate same profit from either activity.
Greater Celestial Essence have stayed the same price for some time on my server so I buy out any below 40g usually. The other Price consideration is that the Inferno Rubys be cut. There’s usually an additional 20g-40g in profit if turned into Brilliant Inferno Rubys.