Gems

Gems were a resource in Dungeon Keeper Online and Dungeon Keeper Mobile.
==Dungeon Keeper Online==
Gems were stored in a Material Warehouse.
==Dungeon Keeper Mobile==
===Overview===
Gems were without doubt the most valuable of the four collectible resources in the game. Although the easiest way to acquire gems was to purchase them with real money, the exorbitant costs made it prohibitive. The game was heavily criticised for this.
Although there were options when it came to spending gems, the most popular and efficient use was to purchase Imps. Other than Imps, gems were typically used to speed up actions such as building or digging, but they could also be used to fully rearm after a raid, fully refill mana, purchase separate gold or stone, or to purchase boosts.
Because gems were the most valuable, most difficult to obtain, and most powerful, they were classed as a premium currency, in contrast with the 'grind' currencies of gold and stone, which were the most abundant, easiest to obtain, and least powerful.
===Acquiring Gems===
Gems could be acquired in many ways without spending real world money in the In-Game Store:
*Using Imps to dig up soft rock or gem veins.
*Completing achievements
*Participating in Exclusive Raids
*Earning Stars in PvP Raids (Gem gains according to star gained)
Beginners' Tip: Gems are your most valuable resource and you don't want to part with them without a very good reason. The best use of your Gems early in the game is to buy more Imps. It costs 800 Gems to buy the third Imp. If you want to minimize or avoid spending real world money on Gems follow this simple strategy and be patient.
During the tutorial do not rush production of anything when Horny tells you to. The wait times at the start are very short and the tutorial will proceed automatically without rushing any build times. After the tutorial is done use your Imps to dig up every Soft Rock block accessible to you.Every block on the dungeon map has a chance to drop resources (ie Gold /Stone) or Gems. Soft Rock takes 4 seconds to dig or 2 seconds with a slapped Imp. Keep an eye on your Treasury and Warehouse limits while you dig because you can’t collect resources from digging blocks if your storage capacity is full. Use the Gold and Stone resources you dig up to upgrade your Treasury and Warehouse rooms to increase your resource capacity. This will also help later on when you want to upgrade rooms that cost more than your initial capacity. As you go you’ll get Gems from completing achievements for many easy things like upgrading rooms and collecting resources. Make sure to claim the rewards, usually 5 gems each time, for completing these achievements. When your storage rooms are upgraded as much as you can start upgrading/building other rooms and traps to offload resources you collect from digging. Make sure to also start on the Campaign mission. They are fairly simple at the start and provide a good amount of resources.
Using this strategy and completing a few of the Exclusive Raids (typically defending your dungeon against waves of attackers) you can collect enough gems to buy the third Imp in just a few days. The third Imp means 3 projects going on at one time and an increase to the slap timer from 30 minutes to 1 hour. This will greatly help when you need to start digging the other blocks which take much longer to clear (2 hours for Gem Vein and 12 hours for Hard Gem Vein) and stand in the way of the other resource collection points.
Similarly, while the Gem cost for the fourth Imp (1200) was quite high, it was possible to save up enough to buy it with a few weeks of playing, which would pay for itself very quickly. The slap-multiplier time of two hours cuts down on much of the grind of the game, and the extra 33% parallel Imp work was a big deal once you reached the mid game. The gems earned for both achievements and event raids went up as you got more powerful, so once you have the third Imp, focusing on building your dungeon and training minions to complete both was a good idea. Once you were within 200-300 gems of the fourth Imp purchase price (probably late in dungeon heart level six), a final push of a couple of days' dedicated digging gem veins could get that extra Imp.
===Spending Gems===
*Their best use was buying Imps until you had six Imps.
*Gems were best used with relevant promotions.
*Wait until there is an immortal sale on before buying Immortals that cost gems.
The game was lambasted for its extortionate gem costs, as well as how many actions required gem payment: purchasing Imps cost hundreds of gems, and hundreds more for each one you had; rush-digging hard gem veins also cost up to 250 gems; even renaming your dungeon (which, although hardly necessary, is still something most players would consider trivial, given that it had no actual effect on gameplay) had a price tag of 50 gems! That is still quite a lot, given that hard gem veins took an entire day to mine out for just nine gems, meaning it could have taken six days to acquire the resources needed just to rename your dungeon!
===Exclusive Raids===
Exclusive Raids were a great way to earn gems. They lasted between one and five days. 
If you completed wave 9, you would earn 16 gems. Completing wave 10 won you 46 gems. The chart below shows that it was worth trying a second time. If you try for a third time, you risked of losing gems, and your only net gain compared to if you had just stopped at your first try (16 gems vs 18 gems) was 2 gems. 
Wave	Gold 	Stone 	Gems	Mana Regen
1 	100 	100 	1 	100
2 	200 	200 	1 	100
3 	400 	400 	1 	100
4 	800 	800 	1 	100
5 	1,200 	1,200 	2 	100
6 	2,000 	2,000 	2 	100
7 	3,000 	3,000 	2 	100
8 	5,000 	5,000 	3 	100
9 	10,000 	10,000 	3 	100
10 	500,000	500,000	30 	100
Gem costs increased with time you wanted to reduce.
===Accelerations===
For the first six minutes, you needed one gem. Every further three minutes, it costed an additional gem. So, first hour costed 19 gems until 59 minutes and 59 seconds.
While a complete first hour costed 20 gems, every further hour of the first day only costed 10 additional gems.
So, 23 hours and 59 minutes costed 249 gems. A complete first day costed 252 gems (added three instead of one gem for last second of the first day).
While a complete first day so costed 252 gems, every further day only costed 120 gems (five per hour) additionally.
====Table====
Time to reduce	Gems needed	Difference
< 6m 	1 	
< 9m 	2 	1 per 3 min
< 1h 	19 	
< 2h 	29 	10 per hour
< 24h 	249 	
1d 	252 	
2d 	372 	120 per day
3d 	492 	
4d 	612 	
5d 	732 	
6d 	852 	
7d 	972 	
8d 	1,092 	
9d 	1,212 	
10d 	1,332 	
==References==