He is majoring in mineralogy at university.

He called me back immediately after he hung up the phone.

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.

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

Plagioclase is one of the main components of the earth's crust.

He was born with the disease of torticollis.

He drew a pattern of rhombus.

He is training his oblique muscles at the gym every day.