---
title: "Quartz — density, melting point and properties"
description: "Quartz has a density of 2,650 kg/m³. Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magnetic."
url: https://atoneplace.net/material/quartz/
site: "At One Place"
---

# Quartz

**Density of quartz: 2,650 kg/m³**

2.65 g/cm³ · 165.4 lb/ft³

The second most abundant mineral in the earth's crust and the reference point at Mohs 7, which is the practical dividing line for scratch resistance — anything softer than quartz gets scratched by ordinary dust, which is mostly quartz. It is piezoelectric, deforming when a voltage is applied and generating one when squeezed, and a quartz plate cut to the right orientation resonates at a temperature-stable frequency: that is the entire basis of quartz timekeeping. Its stiffness, conductivity and expansion are strongly direction-dependent in the crystal, so single figures for those are left off here.

## Properties

- **Density:** 2,650 kg/m³ — 2.65 g/cm³
- **Melting point:** 1,670 °C
- **Hardness:** 7 Mohs
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Watch and clock oscillators
- Optical windows and prisms
- Foundry sand and glassmaking
- Engineered stone worktops

## How it compares

*Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.*

- air: 1.2 kg/m³
- expanded polystyrene foam: 20 kg/m³
- rigid polyurethane foam: 40 kg/m³
- Water — the float line: 1,000 kg/m³
- quartz: 2,650 kg/m³
- tungsten: 19,250 kg/m³
- gold: 19,300 kg/m³
- platinum: 21,450 kg/m³

*Water is 1,000 kg/m³. Anything below that floats.*

| Material | Density | Relative to water |
| --- | --- | --- |
| rigid polyurethane foam | 40 kg/m³ | 0.04× |
| expanded polystyrene foam | 20 kg/m³ | 0.02× |
| air | 1.2 kg/m³ | 0.00× |
| quartz ← | 2,650 kg/m³ | 2.65× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |

## Does it rust?

Quartz contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.

## Is it magnetic?

Quartz is not a metal and has no ferromagnetic response.

## Common questions

### What is the density of quartz?

2,650 kg/m³, or 2.65 g/cm³.

### Does quartz float?

No. At 2,650 kg/m³ it is denser than water.

### Is quartz magnetic?

Quartz is not a metal and has no ferromagnetic response.

## Related pages

- [Does quartz float?](https://atoneplace.net/does-it-float/quartz/)
- [Diamond](https://atoneplace.net/material/diamond/)
- [Granite](https://atoneplace.net/material/granite/)
- [Marble](https://atoneplace.net/material/marble/)
- [Limestone](https://atoneplace.net/material/limestone/)
- [Slate](https://atoneplace.net/material/slate/)
- [Sandstone](https://atoneplace.net/material/sandstone/)

## Sources

- United States Geological Survey — USGS (https://www.usgs.gov/) [Public domain (US Government)]