Precious Gems are found in the treasure chamber of the market. They serve to accelerate the time it takes to construct buildings, clear obstacles, eggs hatch, breed, update your nursery more eggs to keep them as a group grow, treats, make decorations and everything to do with time, except the coliseum. The most important use of the gems is likely to upgrade your nursery as the ability to breed more than one egg can be invaluable.
There are basically two ways to get Gems in DragonVale.
Gems can also be receive for free from friends gifting you. You can receive an infinite amount of gems per day (assuming you had an infinite amount of friends willing to send them to you), but you can only send out three gems a day to people on your friends list. The Strategies page lists a very useful strategy in which a group of four friends. You can only gift your Gems 3 times a day to the other three people in the group (including four of you) and they do the same thing, that as you are guaranteed to get all the gems to 3 per day, no matter what. It is very effective because you are basically three hours can slip away from a breeding season or once a day or building a stockpile of gems and make breeding very quickly in succession.
Note: You can also get free gems in the Colosseum with the victory. For bronze-medal you do zero, you get 2 for silver and for gold you get 5.
Gems can be bought for real money as a treasure by the market monitor. The pictures above show how many Gems you can buy per dollar. Treats such as cash and dragon, you are “incentives” offered Gems when you spend a large sum of money at once. It is one of the staple food of the in-app purchase system and would be without them in the studio or game publishers do not generate revenue from the game.
Now unlike Treats or DragonCash , Gems are probably the only thing worth buying in DragonVale. Treats are easily grown and the rate at which you grow them seems to keep up with the rate of your dragon production and leveling. DragonCash can be eaily obtained after level 14 by breeding the air dragon which takes 2 hours to breed and 2 hours to hatch and sells for 500,000 DragonCash (so you don’t need to worry about that anymore). So if you have the inclination to purchase anything in the game, we’d advise purchasing Gems.