How Much Does a Yard of Rock Weigh? A Comprehensive Guide
Determining the weight of a cubic yard of rock isn't a simple case of providing one number. The weight varies dramatically depending on the type of rock. A cubic yard of lightweight pumice will weigh considerably less than a cubic yard of dense granite. This guide will explore the factors influencing the weight and provide you with a range of weights and helpful information.
What Factors Affect the Weight of a Yard of Rock?
Several key factors influence the weight of a cubic yard of rock:
- Rock Type: This is the most significant factor. Dense, igneous rocks like granite and basalt will be much heavier than sedimentary rocks like sandstone or shale, and even lighter, porous rocks like pumice.
- Moisture Content: Wet rocks will weigh more than dry rocks due to the added weight of the absorbed water. This is particularly significant for porous rocks that absorb more moisture.
- Specific Gravity: This is a measure of the density of a rock compared to the density of water. Higher specific gravity indicates a heavier rock.
- Particle Size and Shape: The size and shape of the individual rocks within the cubic yard can slightly influence the overall weight due to air pockets between larger pieces. Crushed rock, for instance, may have slightly less weight per cubic yard than larger, uniformly sized rocks due to the increased void space.
How Much Does a Cubic Yard of Common Rock Types Weigh?
While precise figures require laboratory testing for each specific rock sample, here's a general range of weights for some common rock types:
- Granite: 165 - 175 lbs per cubic foot (2700 - 2800 lbs per cubic yard)
- Basalt: 160 - 180 lbs per cubic foot (2600 - 2900 lbs per cubic yard)
- Limestone: 150 - 170 lbs per cubic foot (2400 - 2700 lbs per cubic yard)
- Sandstone: 130 - 150 lbs per cubic foot (2100 - 2400 lbs per cubic yard)
- Gravel: 100-110 lbs per cubic foot (1600-1800 lbs per cubic yard) (Note: this varies significantly based on the type of stone used in the gravel.)
- Pumice: This very porous rock can have a significantly lower density and may weigh as little as 30 lbs per cubic foot.
Important Note: These are estimates. Always contact your supplier for the precise weight of the specific type of rock you are purchasing. They should be able to provide you with a weight specification sheet.
How Much Does a Yard of Crushed Rock Weigh?
The weight of a cubic yard of crushed rock also depends heavily on the type of rock being crushed. Generally, crushed rock will be slightly lighter per cubic yard than the same type of rock in larger, uncrushed form due to air pockets between the pieces. Expect the weight to fall within the lower end of the ranges provided above for the specific rock type.
What is the Density of Rock?
The density of rock is expressed in pounds per cubic foot (lbs/ft³) or kilograms per cubic meter (kg/m³). The values above effectively give you a range of densities for different rock types. Remember that density is closely related to specific gravity and is a key factor in calculating the weight of a cubic yard.
How Can I Calculate the Weight of My Specific Rock?
If you need a precise calculation, you should:
- Identify the rock type: This is crucial for accurate estimation.
- Determine the moisture content: Wet rocks weigh more.
- Consult a supplier: They can provide the most accurate weight information for their specific product.
- Perform a density test: If high accuracy is critical, laboratory testing will provide the most precise density measurement.
By understanding the factors that influence the weight of a cubic yard of rock, you can make more informed decisions for your project. Remember to always consult with suppliers to get precise weight figures for your specific needs.
