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 36,412, which is a profit/loss of 987 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Calquat tree seed  1  Common^{[1]}  2,433  
Papaya tree seed  1  Common^{[1]}  30,914  
Palm tree seed  1  Uncommon^{[1]}  104,857 
 ^ ^{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 13,050, which is a profit/loss of 24,349 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Lantadyme seed  2  Common  1,328 
Possibility 3  Grimy torstolsEdit
The expected value of Possibility 3 is 19,312, which is a profit/loss of 18,087 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Grimy torstol  2  Common  7,590 
Possibility 4  RunesEdit
The expected value of Possibility 4 is 120,222, which is a profit/loss of 82,823 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Law rune  50  Common  15,550  
Chaos rune  50  Common  5,450  
Cosmic rune  50  Common  13,250  
Death rune  50  Common  7,300  
Nature rune  50  Common  23,750  
Body rune  200  Common  8,800  
Mind rune  200  Common  3,800  
Earth rune  200  Common  4,000  
Air rune  200  Common  7,200  
Water rune  200  Common  5,400  
Fire rune  200  Common  14,000 
Possibility 5  Iron oreEdit
The expected value of Possibility 5 is 51,522, which is a profit/loss of 14,123 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Iron ore  200 (noted)  Common  39,800 
Possibility 6  CoalEdit
The expected value of Possibility 6 is 32,572, which is a profit/loss of 4,827 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Coal  150 (noted)  Common  20,850 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 53,782, which is a profit/loss of 16,383 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune bar  3  Common  42,060 
Possibility 8  GemsEdit
The expected value of Possibility 8 is 28,096, which is a profit/loss of 9,303 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Uncut diamond  3  Common  10,842  
Uncut ruby  3  Common  5,532 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 44,689, which is a profit/loss of 7,290 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Loop half of a key  1  Common  17,967  
Coins  15,000  Common  15,000 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 47,827, which is a profit/loss of 10,428 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Tooth half of a key  1  Common  21,105  
Coins  15,000  Common  15,000 
Possibility 11  Rune platebodyEdit
The expected value of Possibility 11 is 49,361, which is a profit/loss of 11,962 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune platebody  1  Common  37,639 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 48,682 for male characters and 48,708 for female characters, which is a profit/loss of 11,283 for male characters and 11,309 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune platelegs  1  Common^{[1]}  36,960  
Rune plateskirt  1  Common^{[1]}  36,986 
 ^ ^{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 6,275,766, which is a profit/loss of 6,238,367 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  11,722  
Dragonstone helm  1  Very rare^{[2]}  4,944,831  
Dragonstone hauberk  1  Very rare^{[2]}  11,682,242  
Dragonstone greaves  1  Very rare^{[2]}  5,535,701  
Dragonstone gauntlets  1  Very rare^{[2]}  4,564,159  
Dragonstone boots  1  Very rare^{[2]}  4,593,285 
 ^ 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 63,305.4, which is a profit/loss of 25,906.4 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Yew seed  1  Common  31,462  
Papaya tree seed  1  Common  30,914  
Elder seed  1  Uncommon  133,165 
Possibility 2  Herb seedsEdit
The expected value of Possibility 2 is 14,760, which is a profit/loss of 22,639 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Dwarf weed seed  1  Common  700  
Torstol seed  2  Common  2,338 
Possibility 3Edit
The expected value of Possibility 3 is 26,042, which is a profit/loss of 11,357 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Grimy lantadyme  5  Common  14,320  
Crystal tree blossom  1  Common  Not sold 
Possibility 4  TalismansEdit
The expected value of Possibility 4 is 32,062, which is a profit/loss of 5,337 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Fire talisman  5 (noted)  Common  7,700  
Water talisman  2 (noted)  Common  12,640 
Possibility 5  Rune HalberdEdit
The expected value of Possibility 5 is 87,267, which is a profit/loss of 49,868 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune halberd  1  Common  75,545 
Possibility 6  OresEdit
The expected value of Possibility 6 is 34,882, which is a profit/loss of 2,517 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Coal  80 (noted)  Common  11,120  
Adamantite ore  10 (noted)  Common  12,040  
Corrupted ore  50  Common  Not sold 
Possibility 7  Rune barsEdit
The expected value of Possibility 7 is 53,782, which is a profit/loss of 16,383 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune bar  3  Common  42,060 
Possibility 8  Uncut gemsEdit
The expected value of Possibility 8 is 28,096, which is a profit/loss of 9,303 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Uncut diamond  3  Common  10,842  
Uncut ruby  3  Common  5,532 
Possibility 9  Loop half of a keyEdit
The expected value of Possibility 9 is 29,689, which is a profit/loss of 7,710 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Loop half of a key  1  Common  17,967  
Crystal motherlode shard  10  Common  Not sold 
Possibility 10  Tooth half of a keyEdit
The expected value of Possibility 10 is 32,827, which is a profit/loss of 4,572 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Tooth half of a key  1  Common  21,105  
Crystal motherlode shard  10  Common  Not sold 
Possibility 11  Rune armourEdit
The expected value of Possibility 11 is 62,510, which is a profit/loss of 25,111 if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune full helm  1  Common  19,641  
Rune kiteshield  1  Common  31,147 
Possibility 12  Rune platelegs or plateskirtEdit
The expected value of Possibility 12 is 48,682 for male characters and 48,708 for female characters, which is a profit/loss of 11,283 for male characters and 11,309 for female characters, if buying the crystal key on the GE.
Item  Quantity  Rarity  GE price  

Uncut dragonstone  1  Always  11,722  
Rune platelegs  1  Common^{[1]}  36,960  
Rune plateskirt  1  Common^{[1]}  36,986 
 ^ ^{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 6,275,766, which is a profit/loss of 6,238,367 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  11,722  
Dragonstone helm  1  Very rare^{[2]}  4,944,831  
Dragonstone hauberk  1  Very rare^{[2]}  11,682,242  
Dragonstone greaves  1  Very rare^{[2]}  5,535,701  
Dragonstone gauntlets  1  Very rare^{[2]}  4,564,159  
Dragonstone boots  1  Very rare^{[2]}  4,593,285 
 ^ 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 9,224. 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 4,989. 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
NPCs  
Items 

Rewards 

Locations 

Miscellaneous 

Chests  

Playerowned house 
 
Loot 
 
Thieving 
 
Treasure Trails 
 
Other 
