From Diablo Wiki
Marquise gems are the 15th rank of gem in Diablo 3 and Reaper of Souls. This is the highest level gem in Diablo 3, added in Patch 1.0.7 and it can only be created by crafting up from lower rank gems with the Jeweler. In Reaper of Souls, this gem drops like candy from level 61+ enemies, and is the baseline gem in that game.
This level of gem drop constantly in Reaper of Souls.
In Diablo 3 version 2, post-Auction House, this gem is out of the question. The gold costs are much lower than they were in Diablo 3 vanilla, but it requires 2143 Flawless Square gems which is an untenable number of the gems to collect without an Auction House to purchase them on.
- 3 Radiant Star gems (same type) + 100,000 gold = 1 Marquise gem
- 3 Marquise gems (same type) + 200,000 gold = 1 Imperial gem (Reaper of Souls only.)
 Gem Ranks
A full list of gems by rank. Drop levels are approximate up to 60, with some overlap between each ascending level of gem.
- Chipped gem -- Drops from level 15-20 targets.
- Flawed gem -- Drops from level 21-25 targets. ]
- Regular gem -- Drops from level 26-30 targets.
- Flawless gem -- Drops from level 31-36 targets.
- Perfect gem -- Drops from level 37-42 targets.
- Radiant gem -- Drops from level 43-48 targets.
- Square gem -- Drops from level 49-54 targets.
- Flawless Square gem -- Drops from level 55-60 targets.
- Perfect Square gem -- Upgrade only.
- Radiant Square gem -- Upgrade only.
- Star gem -- Upgrade only.
- Flawless Star gem -- Upgrade only.
- Perfect Star gem -- Upgrade only.
- Radiant Star gem -- Upgrade only.
- Marquise gem -- Upgrade only in D3: Drops lvl 61+ in Reaper of Souls.)
- Imperial gem -- RoS-only. Upgrade, or rarely drops from lvl 61+ on Master+ difficulty.
- Flawless Imperial gem -- Upgrade only. RoS only.
- Royal gem -- Upgrade only. RoS only.
- Flawless Royal gem -- Upgrade only. RoS only.
 Marquise Gem Stats
The stats for all types of Marquise Gems, as of D3v2 and RoS.
|Marquise Star Amethyst||+19% Life||+62 Vitality||Each Hit Adds +700 Life|
|Marquise Star Diamond||Reduces cooldown of all skills by 10.5%||+62 Resistance to All Elements||Increases damage against Elites by 16%|
|Marquise Emerald||+33% Increased Gold Find||+62 Dexterity||Critical Hit Damage Increased by 110%|
|Marquise Ruby||Increases Bonus Experience by 31%||+62 Strength||+190 Damage|
|Marquise Topaz||33% Better Chance of Finding Magical Items||+62 Intelligence||Ranged and Melee attackers take 2500 damage per hit.|
See the gems article for stats and upgrade costs for all ranks and types of gem.
 Diablo 3 Vanilla Marquise Gems
The Marquise Gem was the highest level gem in D3v where it was a luxury only for the well off. The very high crafting cost and huge number of materials required to create it mandated extensive use of the Auction House, and while it can still be crafted in Diablo 3 version 2, the tremendous number of Flawless Square gems required to make it (2143) makes it effectively impossible to create via self finding.
Prior to Diablo 3 patch v1.0.7 there were only 14 levels of gems. Only the lowest eight dropped; the gems from rank 9 and up had to be created by crafting, and level 9-13 had to be taught to the Jeweler from crafting designs. The Marquise gem is learned by another Design, but has much higher creation costs for only slightly better stats, as it was introduced into the game largely as a gold sink for players grown wealthy from using the Auction House.
Marquise gems are considerably more expensive than other games to create and even to unsocket, and and players with less wealth generally ignored them, since the cost of use was far higher than the marginal added benefit. From the official patch notes:
- 3 Radiant Star Gems
- 20 million gold
- 10 Demonic Essence
Un-socketing a Marquise gems costs 5 million gold.
- The designs for the Marquise gems will drop randomly from all level 63 monsters
This gem was also one of the first account bound objects in the game, requiring players to obtain them from lower rank gems and pay the upgrade price themselves. This was a heavy price, since not only did the Marquise cost a lot, but the price had to include all the materials required to create the lower ranking gems.
A Marquise could only be made from 3 Radiant Stars. To create one of those in Diablo 3 vanilla cost:
- 15.4m in Jeweler fees
- 1631 Tomes of Secret
- 729 Flawless Square gems
That made the cumulative cost of a Marquise gem:
- 15.4m x 3 Radiant Stars + 20m = 66.2 million gold in Jeweler fees.
- 1631 ToS x 3 = 4893 Tomes of Secret
- 729 FS gems x 3 = 2187 Flawless Square Gems
- 10 Demonic Essence
Tomes of Secret had a cost, quite a high one in Hardcore, and so did Flawless Squares, which generally put the total cost of a Marquise gem well over 100m gold, though the actual price varied with market conditions (they were often over 150m in Hardcore, due to much higher prices for Tomes of Secret).
 Marquise Gem Economics
There's no way to pinpoint the actual total cost then, since the prices for gems and Tomes of Secret vary widely across time, between patches, and especially between realms and Softcore vs. Hardcore. A quick comparison from a month after the v1.07 patch introduced Marquise Gems:
March 2013 Americas Softcore:
- Tomes of Secret: 400g x 4893 = 1.95m gold
- Flawless Square gems: 700-5500g (Amethyst cheapest, Emerald most expensive) x 2187 = 1.5m - 12m
- Or simply buying 3 Radiant Star Gems: 21m (63m for 3) for Topaz/Ruby/Amethyst, 26m for Emerald (78m for 3)
March 2013 Americas Hardcore:
- Tomes of Secret: 12,000g.
- Flawless Square gems: 220-7700g. (Topaz are cheapest, Amethyst by far the most expensive. Emeralds are only 1200g, 1/3 their price in SC.)
- Or simply buying 3 Radiant Star Gems: Amethyst 75.4m (x3 = 226.2m), Emerald 68m (x3 = 204m), Ruby 72m (x3 = 219m), Topaz 51m (x3 = 153m).
Thus a month after the gem went live, a Marquise Amethyst cost about 82m in Softcore vs. 247m in Hardcore, thanks to +life being very valued in Hardcore, and the vastly higher costs of all the materials to create the item. That's why the most expensive gem in Softcore cost less than half what the least expensive did in Hardcore.
|Items of Diablo III  Item Basics Normal Items Legendary Armor I Legendary Armor II Legendary Weapons 1h Legendary Weapons 2h Item Sets|
|Item Basics||Item Modifiers||Inventory||Artisans||Merchants||Miscellaneous |
|Armor - Class-Specific||Weapons - Class-Specific||Crafting Items||Other Items |
|| • Blacksmith Plans
|Waist||Wrists & Hands||Legs & Feet||Head |
|| Voodoo Masks - WD|
| Chest Armor
|| Amulets cont.
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40) Puzzle Ring
|| Sources - Wiz|
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|| Mighty Weapons - Barb|
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|Diablo 3 and Reaper of Souls Item Sets||Reaper of Souls only |
Torment-Only Class Sets
Torment-only Themed Sets (Not class-restricted)