Release date  22 September 2014 (Update) 

Members  Yes 
Quest  Plague's End 
Location  Prifddinas 
Examine  A crystal key can open it. 
The crystal key chest is a treasure chest located in Ivy Sophista's house in Taverley. A second chest is located in Prifddinas in the Iorwerth Clan district. The chests are locked and can only be opened by a crystal key. Attempting to open the chest without the crystal key yields the message: "This chest is securely locked shut." The crystal key is made up of a loop half of a key and a tooth half of a key; you can make the crystal key by using them with each other, or selecting the "Assemble" option.
Opening a crystal chest grants a variety of rewards, which always include an uncut dragonstone. The crystal chest in Prifddinas grants slightly better rewards than the Taverley chest. The crystal key sells for more than most of the rewards, making it generally more profitable to sell the key than to use it. The key is used once and disappears upon usage.
Rewards possibilitiesEdit
The chest loot always includes an uncut dragonstone, together with a random reward generated from 13 possible reward tables. Below are the values of the chest's contents, based on current Grand Exchange prices. Unless otherwise specified, all possibilities gives all of the listed rewards when obtained.
After an update, wearing a ring of wealth will increase your chances of getting a better drop.
It is only possible to obtain rune platelegs if you are a male character, and a rune plateskirt if you are female character.
Taverley chestEdit
Possibility 1  Fruit tree seedEdit
The expected value of Possibility 1 is 56,729, which is a profit/loss of 17,240 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Calquat tree seed  1  Common^{[1]}  5,855  
Papaya tree seed  1  Common^{[1]}  54,997  
Palm tree seed  1  Uncommon^{[1]}  179,466 
 ^ ^{a} ^{b} ^{c} With Possibility 1, you are guaranteed to get either a calquat tree seed, a papaya tree seed or a palm tree seed. Both the calquat and papaya tree seed have a probability of 5:11 (45.45%), and the palm tree seed has a probability of 1:11 (9%).
Possibility 2  Lantadyme seedsEdit
The expected value of Possibility 2 is 14,766, which is a profit/loss of 24,723 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Lantadyme seed  2  Common  2,012 
Possibility 3  Grimy torstolsEdit
The expected value of Possibility 3 is 22,134, which is a profit/loss of 17,355 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Grimy torstol  2  Common  9,380 
Possibility 4  RunesEdit
The expected value of Possibility 4 is 128,354, which is a profit/loss of 88,865 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Law rune  50  Common  20,750  
Chaos rune  50  Common  5,000  
Cosmic rune  50  Common  14,300  
Death rune  50  Common  8,450  
Nature rune  50  Common  18,500  
Body rune  200  Common  5,600  
Mind rune  200  Common  3,600  
Earth rune  200  Common  4,000  
Air rune  200  Common  9,200  
Water rune  200  Common  5,600  
Fire rune  200  Common  20,600 
Possibility 5  Iron oreEdit
The expected value of Possibility 5 is 55,554, which is a profit/loss of 16,065 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Iron ore  200 (noted)  Common  42,800 
Possibility 6  CoalEdit
The expected value of Possibility 6 is 35,554, which is a profit/loss of 3,935 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Coal  150 (noted)  Common  22,800 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 54,208, which is a profit/loss of 14,719 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune bar  3  Common  41,454 
Possibility 8  GemsEdit
The expected value of Possibility 8 is 33,907, which is a profit/loss of 5,582 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Uncut diamond  3  Common  13,131  
Uncut ruby  3  Common  8,022 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 46,307, which is a profit/loss of 6,818 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Loop half of a key  1  Common  18,553  
Coins  15,000  Common  15,000 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 50,841, which is a profit/loss of 11,352 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Tooth half of a key  1  Common  23,087  
Coins  15,000  Common  15,000 
Possibility 11  Rune platebodyEdit
The expected value of Possibility 11 is 49,944, which is a profit/loss of 10,455 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune platebody  1  Common  37,190 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 49,204 for male characters and 48,781 for female characters, which is a profit/loss of 9,715 for male characters and 9,292 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune platelegs  1  Common^{[1]}  36,450  
Rune plateskirt  1  Common^{[1]}  36,027 
 ^ ^{a} ^{b} With Possibility 12, you are guaranteed to get either a rune platelegs or rune plateskirt. Male characters will always receive a rune platelegs, while female characters will always receive a rune plateskirt.
Possibility 13  Dragonstone armourEdit
The expected value of Possibility 13 is 5,533,705, which is a profit/loss of 5,494,216 if buying the crystal key on the GE.
 Receiving this possibility is very rare, at a rate of 1/6801.^{[1]}
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Dragonstone helm  1  Very rare^{[2]}  4,419,084  
Dragonstone hauberk  1  Very rare^{[2]}  10,097,537  
Dragonstone greaves  1  Very rare^{[2]}  4,901,731  
Dragonstone gauntlets  1  Very rare^{[2]}  4,033,312  
Dragonstone boots  1  Very rare^{[2]}  4,153,093 
 ^ https://twitter.com/JagexTimbo/status/557600452150579200
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} With Possibility 13, you are guaranteed to get exactly one piece of dragonstone armour. Each piece has the same probability of being received.
Prifddinas chestEdit
This chest was released with the first part of Prifddinas on 22 September 2014, and is located in the Iorwerth Manor against the south wall. It has an improved drop table over the chest in Taverley. At the least, the player should still wear a Ring of wealth when opening either crystal chest.
Possibility 1  Tree seedsEdit
The expected value of Possibility 1 is 90,888.2, which is a profit/loss of 51,399.2 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Yew seed  1  Common  46,842  
Papaya tree seed  1  Common  54,997  
Elder seed  1  Uncommon  186,993 
Possibility 2  Herb seedsEdit
The expected value of Possibility 2 is 17,301, which is a profit/loss of 22,188 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Dwarf weed seed  1  Common  981  
Torstol seed  2  Common  3,566 
Possibility 3Edit
The expected value of Possibility 3 is 33,299, which is a profit/loss of 6,190 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Grimy lantadyme  5  Common  20,545  
Crystal tree blossom  1  Common  Not sold 
Possibility 4  TalismansEdit
The expected value of Possibility 4 is 32,674, which is a profit/loss of 6,815 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Fire talisman  5 (noted)  Common  7,230  
Water talisman  2 (noted)  Common  12,690 
Possibility 5  Rune HalberdEdit
The expected value of Possibility 5 is 87,000, which is a profit/loss of 47,511 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune halberd  1  Common  74,246 
Possibility 6  OresEdit
The expected value of Possibility 6 is 37,624, which is a profit/loss of 1,865 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Coal  80 (noted)  Common  12,160  
Adamantite ore  10 (noted)  Common  12,710  
Corrupted ore  50  Common  Not sold 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 54,208, which is a profit/loss of 14,719 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune bar  3  Common  41,454 
Possibility 8  Uncut gemsEdit
The expected value of Possibility 8 is 33,907, which is a profit/loss of 5,582 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Uncut diamond  3  Common  13,131  
Uncut ruby  3  Common  8,022 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 31,307, which is a profit/loss of 8,182 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Loop half of a key  1  Common  18,553  
Crystal motherlode shard  10  Common  Not sold 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 35,841, which is a profit/loss of 3,648 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Tooth half of a key  1  Common  23,087  
Crystal motherlode shard  10  Common  Not sold 
Possibility 11  Rune armourEdit
The expected value of Possibility 11 is 62,600, which is a profit/loss of 23,111 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune full helm  1  Common  19,265  
Rune kiteshield  1  Common  30,581 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 49,204 for male characters and 48,781 for female characters, which is a profit/loss of 9,715 for male characters and 9,292 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Rune platelegs  1  Common^{[1]}  36,450  
Rune plateskirt  1  Common^{[1]}  36,027 
 ^ ^{a} ^{b} With Possibility 12, you are guaranteed to get either a rune platelegs or rune plateskirt. Male characters will always receive a rune platelegs, while female characters will always receive a rune plateskirt.
Possibility 13  Dragonstone armourEdit
The expected value of Possibility 13 is 5,533,705, which is a profit/loss of 5,494,216 if buying the crystal key on the GE.
 Receiving this possibility is very rare, at a rate of 1/6801.^{[1]}
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  12,754  
Dragonstone helm  1  Very rare^{[2]}  4,419,084  
Dragonstone hauberk  1  Very rare^{[2]}  10,097,537  
Dragonstone greaves  1  Very rare^{[2]}  4,901,731  
Dragonstone gauntlets  1  Very rare^{[2]}  4,033,312  
Dragonstone boots  1  Very rare^{[2]}  4,153,093 
 ^ https://twitter.com/JagexTimbo/status/557600452150579200
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} With Possibility 13, you are guaranteed to get exactly one piece of dragonstone armour. Each piece has the same probability of being received.
ProbabilitiesEdit
Taverley chestEdit
 The probabilities in this section are an estimation based on the data of 1134 crystal chest loots on the Taverley chest, while wearing a ring of wealth.
Possibility  Percentage 

Possibility 1: Fruit tree seed  8.02%^{[notes 1]} 
Possibility 2: Lantadyme seeds  9.61% 
Possibility 3: Grimy torstols  9.96% 
Possibility 4: Runes  7.5% 
Possibility 5: Iron ore  8.47% 
Possibility 6: Coal  9.17% 
Possibility 7: Rune bars  9.61% 
Possibility 8: Gems  9.61% 
Possibility 9: Loop half of a key  7.94% 
Possibility 10: Tooth half of a key  6.61% 
Possibility 11: Rune platebody  5.03% 
Possibility 12: Rune platelegs or plateskirt  8.47% 
Possibility 13: Dragonstone armour  < 0.01% 
 ^ The official RuneScape wiki lists the probability of receiving a calquat or papaya tree seed at 5:11 (45.45%) each and the probability of receiving a palm tree seed at 1:11 (9%). This data shows a probability of 49.45% for the calquat, 47.25% for the papaya, and 3.30% for the palm tree seed.
Using these probabilities, the expected average profit/loss, per crystal key, when looting the crystal chest is 8,461. Assuming you will receive whichever of the rune platelegs and rune plateskirt is worth more, and the crystal key is bought at GE price. This is excluding the possibility of receiving a dragonstone armour piece, as this possibility is much too rare to estimate with any acceptable accuracy.
Prifddinas chestEdit
 The probabilities in this section are an estimation based on the data of 20.000 loots of the Prifddinas crystal chest, while wearing luck of the dwarves. The loot from the Prifddinas chest is not affected by the Voice of Seren.^{[1]}
Possibility  Percentage 

Possibility 1: Tree seeds  7.59% 
Possibility 2: Herb seeds  7.555% 
Possibility 3: Grimy lantadymes  4.47% 
Possibility 4: Talismans  7.545% 
Possibility 5: Rune Halberd  6.00% 
Possibility 6: Ores  10.36% 
Possibility 7: Rune bars  9.455% 
Possibility 8: Gems  9.525% 
Possibility 9: Loop half of a key  9.30% 
Possibility 10: Tooth half of a key  9.045% 
Possibility 11: Rune full helm and rune kiteshield  8.81% 
Possibility 12: Rune platelegs or plateskirt  10.34% 
Possibility 13: Dragonstone armour  < 0.01% 
Using these probabilities, the expected average profit/loss, per crystal key, when looting the crystal chest is 5,791. Assuming you will receive rune platelegs, the crystal key is bought at GE price and the luck of the dwarves ring is worn. This is excluding the possibility of receiving a dragonstone armour piece, as this possibility is much too rare to estimate with any acceptable accuracy.
Estimate probabilities for nonguaranteed loot are:
 17.785% chance of crystal motherlode shard when rolling possibility 9 or 10. This assumes that possibility 9 and 10 yield the same chance for crystal motherlode shards.
 8.675% chance of recieving elder seed when rolling possibility 1.
 63.385% chance of recieving papaya tree seed when rolling possibility 1.
 27.94% chance of recieving yew seed when rolling possibility 1.
 20.39% chance of recieving dwarf weed seed when rolling possibility 2.
 79.61% chance of recieving torstol seed when rolling possibility 2.
TriviaEdit
 The crystal key chest was reworked on 11 June 2013 with the release of the Triskelion Treasures. Previous old drops, such as receiving 2,000 coins and a Spinach roll along with an Uncut dragonstone, were removed, and new ones were added, such as the Dragonstone armour.
ReferencesEdit
Chests  

Playerowned house 
 
Loot 
 
Thieving 
 
Other 
