Thanks for Trial, we all know how much gem cost with out any skill :

60 for G1 240 for combine.
So a G2 gem cost is 60+60+240=360

We can see clearly, the cost of gem is mainly it's combining cost.Even if you trade you soul with forgotten for a 0 cost gem.After a few grade up, it's cost will rising and end up preety much same as any other gem.

Classic demon shenanigans.

With every grade up,the cost of gem is nearly double.

1. 60
   
2. 360
   
3. 960
   
4. 2160
   
5. 4560
   
6. 9360
   
7. 18960
   
8. 38160

Or in formula : Mana cost= 2^(G-1)*30+(2^(G-1)-1)*240

Every gem has 2 power:
it's raw DPS
and it;s special color related power.

In this guild i will focus on special color only. Becouse the raw DPS are very close among 6 color.


Because with each grade,the cost is double,we hope the special power is also double to keep up.
But there is no such thing as hope.
Take look at purple gem

the armor it reduce is 2/3.8/7.22.Only a 1.9 time of increase.
With every grade make it 2 times more cost,it only reduce 1.9 times armor.

The growth rate is only1.9,as for green it's 1.8,and for orange is 1.38.

growth rate is define as:

Gem-power/ Gem-power of previous grade
If this number is the same in all grade.
then this number is it's growth rate.


Blue is a ltlle bit speical, as agentronin316 kindly point out, a 10% slower means monster take 111% more time to reach orb. (1/0.1=1.11)

We should consider the power of blue gem in term of time increase rather then the slow percentage.
After this correction we can see blue still sit in the bottom.
Time mob takes to reach orb only increase 103% with each grade.Compare to Purple's 190%.

Some wizard attempt to compare the power between different color,may want to draw a plot indicate the power and grade of each gem.


well this plot can tell us very little thing.

It's mainly because the magnitude is so different.

To unlock the arcanic secret of gemcrafting,we must seek guidence from math,more specifically Logmatiic function.
Since we are discussing doubling, i am using base 2 for log.

log(gempower) in base 2
I add in the imaginary hope gem(black),as reference.It double it's power every time it's cost double.



this is much better now,then i move all plot vertically a little so they all line up in (0,0)



Now the arcanic secret is well exposed.

In term of power growth rate, the colors order are :
P>G>O>Y>R>>>>>>>>B

In early game,under wizard lv 100 Green and purple are in deed powerful and useful.
They have the best power growth rate,Nearly 2.
But after beating final boss and enter the post-game,they become less useful.

Also in lower WL (before you can create L12 gem), dual color has better raw DPS .In lower level the raw DPS bonus out weight special color bonus.But after you can create L12 gem and start to work the way up to infinity, special power,especially mana leech is much more important.

The orange need a lot of skill point and set up to work,it grow slower but the return is great it gives you more mana to play with !
If you set up correctly you should harvet 10~1000 more mana then killing monster.This is op. This why special power is the most inportant aspect in post-game.
Once you can create LV 12 gem and set up trap-amp for mana farm, Orange is the best color to invest you mana.
New wizard should try if they can set up mana farm. The color choice go thru a Paradigm shift after you can harvet mana from monster.


Yellow gem has very low growth rate, you need a good mana income to feed it up.
A 100 times critical damage is identical to ignore armor.So player in post-game normally just use Y instead of P becouse they can afford the more expensive Y gem with op mana farm.
FYI,the crit rate is cap at 80%,but the crit multiplier has no cap.

Red gem has second lowest growth rate only 1.16, i never use it other then trail.

Blue is slow.They grow up and up grade up slow.In most of time a 40% slower rate is all you ever need.It's really not worth to upgrade more then that. Just freeze them already.
Blue also has the best raw DPS, but i doubt any one will use blue instead of Y as their killer gem.