Not really part of the original topic, but actually, both icons reasonably could represent Quartz, and neither is really appropriate for Silicon. Quartz is silicon dioxide ( SiO2, 2 should be subscripted but I don't know how to do that here), which is the most common constituent of sand. Quartz also exists as crystals, as seen in many exhibits of rocks and minerals. Silicon is a semiconductor, a non-metallic element. "It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor." The most appropriate icon for silicon would probably be a semiconductor wafer. So quartz ( I would guess usually in the form of sand ) is a raw material for silicon. In addition to being used to make the semiconductors used in electronic equipment, silicon is used to make bricks, Portland cement, and for alloys of aluminum and steel. So an alternate icon for silicon could be derived from one of those products.
I am perfectly happy with the icons as they are. They function perfectly just as they are within the context of the game.