Design: Magegems [5, 5, 5]
"Anti-Magic" is a bit of a misnomer, when it comes to our anti-magic gems. They don't stop magic, exactly - they absorb magic in the surrounding area and convert the magical energy into a harmless, annoying hum. It stands to reason, then, that if we make it stop humming, the gem will store the energy instead.
We still run into the same problem with exploding gemstones, but we've pretty much hammered it out. Depending on the size and quality of the stone we can empirically figure out how much energy it can safely store - a bit of clever magic shows this as a glow in the crystal that diminishes as the magic is used up. This glowing display is represented as a "fluid" that drains down, giving a quick visual display of how much energy is left.
Magegems are quantified by size; A is currently the largest we can manufacture, AA is slightly smaller, and AAA is the smallest we can make. An A magegem could concievably power a couple flare spells, although smaller gems hooked in series could allow more continuous effect to persist for longer before they're exhausted.
Magegems do not passively pull from the air like anti-magic gems, but are also immune to anti-magic gem effects. Each gem must be charged by a mage over a period of an hour or so before they're at full capacity, but can be recharged once spent. They are fully compatible with your solid-gold circuitry, and can be slotted in and out as needed.
AAA gems are Cheap.
AA gems are Expensive.
A gems are Very Expensive.