A storage and mixing capsule 10 for separately storing a pair of ingredients therein and providing a structure for efficiently and reliably mixing the ingredients to form an amalgam. The capsule has two components: a first receptacle 12 and a second receptacle 14. The first receptacle 12 includes an interior compartment 16 for receiving an alloy and includes a piercing element 24 attached to a portion of the inner wall 26. The second receptacle 14 includes an interior compartment 30 for receiving mercury. The second receptacle 14 further includes a rupturable seal 38 disposed across the open bottom end 36 of the second receptacle 14. The capsule 10 further includes a conduit 54 extending from the capsule 10 which is used as a passageway for air to move from the interior of the capsule 10 to the exterior of the capsule 10 or for an inert gas to move from the exterior of the capsule 10 to the interior of the capsule 10 to create an interior atmosphere which prevents the oxidization of amalgam components. The second receptacle 14 is additionally adapted to be received by the first receptacle 12 and the two receptacles 12, 14 are movable relative one to another in order to bring the piercing element 24 into confronting relationship with the rupturable seal 38 in order to rupture the rupturable seal 38 and mix the components.