A crystal or the process of crystallization — a solid with a regular internal structure, or the act of forming such a structure.
塩水を蒸発させて小さな塩の結晶を作った。
I evaporated saltwater and made small salt crystals.
この物質は低温で結晶構造をとる。
This substance takes on a crystalline structure at low temperatures.
冷却すると溶液が結晶化することがある。
Upon cooling, the solution may crystallize.
Figuratively, the concrete result or fruit of long effort or union (e.g., 'the fruit of labor', 'the product of love').
この論文は彼の長年の研究の結晶だ。
This paper is the culmination (the fruit) of his years of research.
あの赤ちゃんは二人の愛の結晶だ。
That baby is the product of their love.
新製品はチームの努力の結晶として市場に出た。
The new product hit the market as the result of the team's effort.