Currently 3 re-skins of the Gem resource:
Ruby
Sapphire
Emerald
One re-skin of the Copper resource:
Download here.
Defines
Ruby

Sapphire

Emerald

One re-skin of the Copper resource:
Amber
Download here.
Defines
Spoiler :
Code:
INSERT INTO ArtDefine_Landmarks (Era, State, Scale, ImprovementType, LayoutHandler, ResourceType, Model, TerrainContour) VALUES
('Any', 'Any', 1, 'ART_DEF_IMPROVEMENT_NONE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/Emerald.fxsxml', 1),
('Industrial', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/MED_Mine_Emerald.fxsxml', 1),
('Industrial', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/HB_MED_Mine_Emerald.fxsxml', 1),
('Industrial', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/PL_MED_Mine_Emerald.fxsxml', 1),
('Ancient', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/IND_Mine_Emerald.fxsxml', 1),
('Ancient', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/HB_IND_Mine_Emerald.fxsxml', 1),
('Ancient', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_EMERALD', 'Art/Emerald/PL_IND_Mine_Emerald.fxsxml', 1),
('Any', 'Any', 1, 'ART_DEF_IMPROVEMENT_NONE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/Ruby.fxsxml', 1),
('Industrial', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/MED_Mine_Ruby.fxsxml', 1),
('Industrial', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/HB_MED_Mine_Ruby.fxsxml', 1),
('Industrial', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/PL_MED_Mine_Ruby.fxsxml', 1),
('Ancient', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/IND_Mine_Ruby.fxsxml', 1),
('Ancient', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/HB_IND_Mine_Ruby.fxsxml', 1),
('Ancient', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_RUBY', 'Art/Ruby/PL_IND_Mine_Ruby.fxsxml', 1),
('Any', 'Any', 1, 'ART_DEF_IMPROVEMENT_NONE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/Sapphire.fxsxml', 1),
('Industrial', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/MED_Mine_Sapphire.fxsxml', 1),
('Industrial', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/HB_MED_Mine_Sapphire.fxsxml', 1),
('Industrial', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/PL_MED_Mine_Sapphire.fxsxml', 1),
('Ancient', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/IND_Mine_Sapphire.fxsxml', 1),
('Ancient', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/HB_IND_Mine_Sapphire.fxsxml', 1),
('Ancient', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_SAPPHIRE', 'Art/Sapphire/PL_IND_Mine_Sapphire.fxsxml', 1),
('Any', 'Any', 1, 'ART_DEF_IMPROVEMENT_NONE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/Amber.fxsxml', 1),
('Ancient', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/HB_MED_Amber_Mine.fxsxml', 1),
('Ancient', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/MED_Mine_Amber.fxsxml', 1),
('Ancient', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/PL_MED_Mine_Amber.fxsxml', 1),
('Industrial', 'UnderConstruction', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/HB_IND_Amber_Mine.fxsxml', 1),
('Industrial', 'Constructed', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/IND_Mine_Amber.fxsxml', 1),
('Industrial', 'Pillaged', 1, 'ART_DEF_IMPROVEMENT_MINE', 'SNAPSHOT', 'ART_DEF_RESOURCE_AMBER', 'Art/Amber/PL_MED_Mine_Amber.fxsxml', 1);
INSERT INTO ArtDefine_LandmarkTypes (Type, LandmarkType, FriendlyName) VALUES
('ART_DEF_RESOURCE_EMERALD', 'Resource', 'Emerald'),
('ART_DEF_RESOURCE_SAPPHIRE', 'Resource', 'Sapphire'),
('ART_DEF_RESOURCE_RUBY', 'Resource', 'Ruby'),
('ART_DEF_RESOURCE_AMBER', 'Resource', 'Amber');