2.66 g/cm³ (true density), 1.6–1.8 tons/cubic meter (bulk density)
The density of pebbles varies depending on the measurement method and composition, and is mainly divided into the following two categories:
True density
Refers to the density of pure material after excluding voids, which is generally 2.66 g/cm³, and this data is consistent in multiple authoritative sources. Its composition is mainly silicon dioxide (accounting for more than 95%), and contains trace elements such as iron and copper, resulting in a variety of colors.
Bulk density (stacking density)
Considering the void ratio when actually stacked, it is usually 1.6–1.8 tons/cubic meter (or 16–18 kN/m³). For example:
5–10 cm pebbles have a void ratio of 70%, and the actual density is about 1.65 tons/cubic meter;
The bulk density of machine-made pebbles or river pebbles may fluctuate slightly depending on the type.
Conversion relationship: 1 ton of pebbles has a volume of about 0.56–0.63 cubic meters. Note that riverbed pebbles made of granite may have a higher density (2.63–3.3 g/cm³).