Edison format ruling
Gigastone Omega

Card text as printed in this era© Can't be Normal Summoned/Set.
© Must first be Special Summoned (from your hand) by banishing 2 EARTHs from your GY.
① If this face-up card you control is sent to the GY by card effect:
Destroy all Spells/Traps your opponent controls.
Rulings
- As long as this card was initially Special Summoned by its own procedure (and the summon wasn't negated), you can Summon it from the GY with card effects.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.