Constant is a Specification of the Consequence Property.

When a resource is consumed, the consequence can be Diminish, Invest or Constant.

When an Effect is Constant, the Resource can be spent on something that has a constant impact on the rest of the game session. Usually in the form of Abstracts or objects or a permanent effect. such as building units or buildings in Starcraft 2, buying items in Diablo 2, or releasing matter in Osmos.

Spending money on units in Starcraft 2, for instance, can can perform a constant amount of damage on the enemy unless killed. Using a nuke has a huge effect on impact, but its effect diminish over time.

Is always found in Archetypes:
Material, Skill Point, Physical

Is occasionally found in Archetypes:
Currency, Rage, Action

Is found in games:
Bioshock 2 (Adam)
Crysis 2 (Nano-Collection)
Deus Ex 2 (Credits, Experience Points)
Diablo 2 (Gems/runes, Stat Points, Skill Points)
Farmville (Farmcoins, Farmcash, Bushels, Building Materials)
From Dust (Elements)
KoA; Reckoning (Skill Points, Ability Points, Gems, Materials)
KB; Armored Princess (Gold, Runes)
League of Legends (Runes, Mastery Points, Hero Skill Points, Riot Points)
Majesty (Gold, Health)
Osmos (Matter)
Plants vs. Zombies (Sun, Coins)
Puzzle Quest 2 (Gem Reserves, Gold, Materials)
Revenge of the Titans (Dollars, Turret Quantity)
Rock of Ages (Money)
Starcraft 2 (Minerals, Vespene, Research Points, Credits)
Team Fortress 2 (Metal)
Terraria (Non-Comsumable, Coins, resources)
Word Feud (Letters)
World of Goo (Goo).