Artifact, {1}, {T}: Put a charge counter on Jeweled Amulet. Note the type of mana spent to pay this activation cost. Activate this ability only if there are no charge counters on Jeweled Amulet.
Uncommon
{T}, Remove a charge counter from Jeweled Amulet: Add one mana of Jeweled Amulet's last noted type to your mana pool.
Illus. Dan Frazier

10/1/2008: The types of mana are white, blue, black, red, green, and colorless.
10/1/2008: Charge counters are indistinguishable from one another. If some other spell or ability (such as Power Conduit's ability) puts a charge counter on Jeweled Amulet, activating Jeweled Amulet's second ability will still check the type of mana last noted by its first ability. If there is no type of mana noted by its first ability (because it hasn't been activated by that point), the second ability will produce no mana.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander