“由小粒而成的”可以翻译为 “composed of or formed from small particles” 或者更简洁地表达为 “made up of small particles” 。具体使用哪个表达可以根据上下文和表达重点来选择。例如：
This material is composed of/formed from small particles, which gives it its unique properties.（这种材料由小粒构成，这赋予了它独特的性质。）
The structure is made up of small particles tightly packed together.（这个结构是由紧密排列的小粒组成的。）