This room is covered with soundproofing material, so the sound doesn't leak outside.

He honked the car horn to get my attention.

We are aiming to kill two birds with one stone with this plan.

His words held a double surprise, like 'isseki-rokuto'.

This mineral is called ulexite and has special optical properties.

This stone is a mineral called clinozoisite.

This beautiful stone is a mineral called clinozoisite.

He succeeded in a difficult project with the spirit of 'ishi no ue ni mo sannen', which means great works are performed by perseverance.

Infrasound is a type of sound that is inaudible to the human ear.

Debuccalization refers to the phenomenon in phonetics where a specific sound is pronounced outside the oral cavity.