The Seal of Orichalcos vs another Field Spell

I have see many questions about this thats why i make it clear here. If Seal of Orichalcos is currently on the field, and either you or an opponent activate another Field Spell, Seal is "destroyed" isn't protected by its "Once per turn: cannot be destroyed by card effects" because Seal is being destroyed by a Game Mechanic, not a Card Effect; therefore, it can be "destroyed" in this scenario