Translation of "Opaque" in Spanish

You don't know what that small opaque bottle contains.

No sabéis qué contiene esa botellita opaca.

Listening to a Portuguese conversation is an unreal experience. A completely opaque string of phonemes, occasionally punctuated by a crystal-clear "Sim, senhor."

Escuchar una conversación en portugués es una experiencia irreal, un barullo interminable de fonemas apuntillados por un «Sim, senhor.» perfectamente claro.

When Scrooge awoke, it was so dark, that looking out of bed, he could scarcely distinguish the transparent window from the opaque walls of his chamber.

Cuando Scrooge despertó, estaba tan oscuro, que, mirando de la cama, apenas podía distinguir de la ventana transparente las paredes opacas de su habitación.