[pfdietz]

I remember when I worked at Motorola some decades ago, there was a little section in the factory area in Schaumburg that made quartz crystals. It's all long since been sold off (I think all the equipment went to China) but I remember all the signs for cyanide alarms, presumably due to some step in the manufacturing process.

The quartz crystals themselves were grown with carefully controlled levels of specific impurities (like scandium) in order to reduce their temperature sensitivity.

[adrian_b]

They may have had baths for galvanic deposition of silver. Those typically used cyanide solutions.

Galvanic deposition of silver has been frequently used for increasing the thickness of thin metal layers that had been deposited in vacuum, in order to adhere to the crystal.