From Diablo Wiki
Imperial gems are the 16th rank of gem and only found in Reaper of Souls. This is the first level of gem only found in Reaper of Souls, and while Marquise gems are the usual drop from lvl 61+ targets, Imperial gems can drop from those targets on Master and higher difficulty levels.
This level of gem drops occasionally in Reaper of Souls, but is more often crafted up from three Marquise gems.
- 3 Marquise gems (same type) + 200,000 gold = 1 Imperial gem (Reaper of Souls only.)
- 3 Imperial gems (same type) + 300,000 gold = 1 Flawless Imperial gem
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.
Imperial Gem Stats
The stats for all types of Imperial Gems, as of Reaper of Souls v2.0.4.
|Imperial Amethyst||+20% Life||+100 Vitality||Each Hit Adds +800 Life|
|Imperial Diamond||Reduces cooldown of all skills by 11%||+66 Resistance to All Elements||Increases damage against Elites by 17%|
|Imperial Emerald||+35% Increased Gold Find||+100 Dexterity||Critical Hit Damage Increased by 115%|
|Imperial Ruby||Increases Bonus Experience by 35%||+100 Strength||+220 Damage|
|Imperial Topaz||35% Better Chance of Finding Magical Items||+100 Intelligence||Ranged and Melee attackers take 3100 damage per hit.|
See the gems article for stats and upgrade costs for all ranks and types of gem.
|Items of Diablo III  Item Basics Normal Items Crafting Legendary Armor I Legendary Armor II Legendary Weapons 1h Legendary Weapons 2h Item Sets|
|Item Basics||Item Affixes||Interface||Artisans||Miscellaneous |
• Prefixes & Suffixes
|Diablo 3 and Reaper of Souls Item Sets||Reaper of Souls only |
Crafted Item Sets
Crafted Item Sets
Themed Item Sets