How do atoms differ from one another in Lucretius’s philosophy?

In the philosophy of Lucretius, as detailed in his work De rerum natura, atoms are considered the fundamental, indivisible, and everlasting building blocks of the universe. While all atoms share these immutable characteristics, they differ from one another in three specific ways: shape, size, and weight.1

These atoms are composed of inseparable minimal units; larger atoms contain more of these units, though even the largest remain minute. The physical properties of the objects we perceive are determined by how these atoms, with their varying shapes and sizes, combine and move within the void. For instance, atoms may cohere more or less strongly depending on their specific shapes, and all change in the material world is explained by the addition, subtraction, or rearrangement of these changeless particles.1

By postulating that atoms differ only in these quantitative properties, Lucretius maintained the Epicurean view that the infinite variety of the natural world arises from the mechanical interaction of a finite number of atomic kinds.1