Good mix of active and idle play!
"Amethyst Teir [x]" 's tooltip indicates that it has an increase to the JADE spawn rate.
The scaling seems a bit off - I've acquired every upgrade, to max tier, and have performed full field sweeps multiple times most-upgrade, and still haven't acquired an instance of the second-to-last computer type. Since the Silicon acquiring rate can't be boosted anymore and the mutually-supported cycles between the Silicon/Coin Active/Idle gameplay loops no longer exists with the tiers maxed out, I'm quitting 'early' before getting the Quantum Computer.
Even a declared goal of "Acquire a Quantum Computer" or "Be a Coin Millionaire!" would keep the game going, I think.