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 give 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 a female character.
Taverley chestEdit
Possibility 1  Fruit tree seedEdit
The expected value of Possibility 1 is 31,681, which is a profit/loss of 4,565 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Calquat tree seed  1  Common^{[1]}  1,318  
Papaya tree seed  1  Common^{[1]}  23,005  
Palm tree seed  1  Uncommon^{[1]}  103,049 
 ^ ^{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 12,375, which is a profit/loss of 23,871 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Lantadyme seed  2  Common  1,118 
Possibility 3  Grimy torstolsEdit
The expected value of Possibility 3 is 18,349, which is a profit/loss of 17,897 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Grimy torstol  2  Common  7,092 
Possibility 4  RunesEdit
The expected value of Possibility 4 is 126,207, which is a profit/loss of 89,961 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Law rune  50  Common  21,250  
Chaos rune  50  Common  6,450  
Cosmic rune  50  Common  20,350  
Death rune  50  Common  7,300  
Nature rune  50  Common  21,800  
Body rune  200  Common  6,200  
Mind rune  200  Common  3,800  
Earth rune  200  Common  4,000  
Air rune  200  Common  6,400  
Water rune  200  Common  4,800  
Fire rune  200  Common  12,600 
Possibility 5  Iron oreEdit
The expected value of Possibility 5 is 47,457, which is a profit/loss of 11,211 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Iron ore  200 (noted)  Common  36,200 
Possibility 6  CoalEdit
The expected value of Possibility 6 is 30,607, which is a profit/loss of 5,639 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Coal  150 (noted)  Common  19,350 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 52,741, which is a profit/loss of 16,495 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune bar  3  Common  41,484 
Possibility 8  GemsEdit
The expected value of Possibility 8 is 24,742, which is a profit/loss of 11,504 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Uncut diamond  3  Common  8,976  
Uncut ruby  3  Common  4,509 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 43,313, which is a profit/loss of 7,067 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Loop half of a key  1  Common  17,056  
Coins  15,000  Common  15,000 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 45,724, which is a profit/loss of 9,478 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Tooth half of a key  1  Common  19,467  
Coins  15,000  Common  15,000 
Possibility 11  Rune platebodyEdit
The expected value of Possibility 11 is 49,122, which is a profit/loss of 12,876 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune platebody  1  Common  37,865 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 48,486 for male characters and 48,487 for female characters, which is a profit/loss of 12,240 for male characters and 12,241 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune platelegs  1  Common^{[1]}  37,229  
Rune plateskirt  1  Common^{[1]}  37,230 
 ^ ^{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 6,504,853, which is a profit/loss of 6,468,607 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  11,257  
Dragonstone helm  1  Very rare^{[2]}  5,156,569  
Dragonstone hauberk  1  Very rare^{[2]}  12,191,138  
Dragonstone greaves  1  Very rare^{[2]}  5,789,526  
Dragonstone gauntlets  1  Very rare^{[2]}  4,564,159  
Dragonstone boots  1  Very rare^{[2]}  4,766,589 
 ^ 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 50,046.8, which is a profit/loss of 13,800.8 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Yew seed  1  Common  29,417  
Papaya tree seed  1  Common  23,005  
Elder seed  1  Uncommon  89,105 
Possibility 2  Herb seedsEdit
The expected value of Possibility 2 is 14,209, which is a profit/loss of 22,037 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Dwarf weed seed  1  Common  684  
Torstol seed  2  Common  2,268 
Possibility 3Edit
The expected value of Possibility 3 is 25,722, which is a profit/loss of 10,524 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Grimy lantadyme  5  Common  14,465  
Crystal tree blossom  1  Common  Not sold 
Possibility 4  TalismansEdit
The expected value of Possibility 4 is 36,059, which is a profit/loss of 187 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Fire talisman  5 (noted)  Common  9,910  
Water talisman  2 (noted)  Common  14,892 
Possibility 5  Rune HalberdEdit
The expected value of Possibility 5 is 86,802, which is a profit/loss of 50,556 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune halberd  1  Common  75,545 
Possibility 6  OresEdit
The expected value of Possibility 6 is 34,377, which is a profit/loss of 1,869 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Coal  80 (noted)  Common  10,320  
Adamantite ore  10 (noted)  Common  12,800  
Corrupted ore  50  Common  Not sold 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 52,741, which is a profit/loss of 16,495 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune bar  3  Common  41,484 
Possibility 8  Uncut gemsEdit
The expected value of Possibility 8 is 24,742, which is a profit/loss of 11,504 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Uncut diamond  3  Common  8,976  
Uncut ruby  3  Common  4,509 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 28,313, which is a profit/loss of 7,933 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Loop half of a key  1  Common  17,056  
Crystal motherlode shard  10  Common  Not sold 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 30,724, which is a profit/loss of 5,522 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Tooth half of a key  1  Common  19,467  
Crystal motherlode shard  10  Common  Not sold 
Possibility 11  Rune armourEdit
The expected value of Possibility 11 is 62,603, which is a profit/loss of 26,357 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune full helm  1  Common  19,927  
Rune kiteshield  1  Common  31,419 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 48,486 for male characters and 48,487 for female characters, which is a profit/loss of 12,240 for male characters and 12,241 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,257  
Rune platelegs  1  Common^{[1]}  37,229  
Rune plateskirt  1  Common^{[1]}  37,230 
 ^ ^{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 6,504,853, which is a profit/loss of 6,468,607 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  11,257  
Dragonstone helm  1  Very rare^{[2]}  5,156,569  
Dragonstone hauberk  1  Very rare^{[2]}  12,191,138  
Dragonstone greaves  1  Very rare^{[2]}  5,789,526  
Dragonstone gauntlets  1  Very rare^{[2]}  4,564,159  
Dragonstone boots  1  Very rare^{[2]}  4,766,589 
 ^ 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 1000 crystal chest loots on the Taverley chest, while wearing a luck of the dwarves.
Possibility  Percentage 

Possibility 1: Fruit tree seed  6.4%^{[notes 1]} 
Possibility 2: Lantadyme seeds  7.9% 
Possibility 3: Grimy torstols  9.4% 
Possibility 4: Runes  10% 
Possibility 5: Iron ore  9.1% 
Possibility 6: Coal  9.8% 
Possibility 7: Rune bars  9.4% 
Possibility 8: Gems  8.3% 
Possibility 9: Loop half of a key  7.4% 
Possibility 10: Tooth half of a key  6.8% 
Possibility 11: Rune platebody  7.2% 
Possibility 12: Rune platelegs or plateskirt  8.3% 
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 48.45% for the calquat, 42.18% for the papaya, and 9.37% for the palm tree seed.
Using these probabilities, the expected average profit/loss, per crystal key, when looting the crystal chest is 9,310. 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 4,550. 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 receiving elder seed when rolling possibility 1.
 63.385% chance of receiving papaya tree seed when rolling possibility 1.
 27.94% chance of receiving yew seed when rolling possibility 1.
 20.39% chance of receiving dwarf weed seed when rolling possibility 2.
 79.61% chance of receiving 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.
 The estimated dragonstone armour possibility chance is about 0.000147%.
ReferencesEdit
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