This work reports on the synthesis of hollow particles of amorphous calcium silicate hydrate (C-S-H). A template assisted synthesis involving skimmed natural rubber latex, sodium silicate and a calcium source (calcium nitrate and calcium hydroxide in different experiments) was used. Characteristics of the particles were affected by the type of the calcium source, the concentration of sodium silicate and the initial pH used in the preparation process. The formation of hollow particles was mainly controlled by the release rate of Ca2+ from the source material. The shell thickness of the particles and the fraction of solids in them were influenced by the concentration of sodium silicate used. The size of the particles was most influenced by the initial pH. In the wavelength range of 290-900 nm, the lightweight hollow particles were highly reflective and thus have good prospects as ultraviolet/visible-blocking materials.