---
title: "Platinum — density, melting point and properties"
description: "Platinum has a density of 21,450 kg/m³. Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magnetic."
url: https://atoneplace.net/material/platinum/
site: "At One Place"
---

# Platinum

**Density of platinum: 21,450 kg/m³**

21.45 g/cm³ · 1339.1 lb/ft³

Denser than gold at 21,450 kg/m³, and one of the few metals that can be worked as a crucible material for molten glass and oxides because it neither melts nor reacts. Platinum resistance thermometers are the defining instrument of the international temperature scale from -200 °C to over 900 °C, precisely because the metal is so reproducible. Most of the world's production is not jewellery but catalysis, which is why catalytic converter theft tracks the metal price.

## Properties

- **Density:** 21,450 kg/m³ — 21.45 g/cm³
- **Melting point:** 1,768.3 °C
- **Tensile strength:** 125–240 MPa
- **Young's modulus:** 168 GPa
- **Thermal conductivity:** 71.6 W/(m·K)
- **Thermal expansion:** 8.8 µm/(m·K)
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Catalytic converters and fuel cell catalysts
- Laboratory crucibles and thermocouples
- Spark plug electrodes
- Jewellery

## 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
- 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× |
| platinum ← | 21,450 kg/m³ | 21.45× |

## Does it rust?

Platinum does not corrode in air or water. That chemical inertness is much of why it has been used for coinage and contacts for millennia.

## Is it magnetic?

Platinum is not ferromagnetic. It is often assumed to be because it is a metal, but most metals are not — only iron, nickel, cobalt and a few alloys are attracted to an ordinary magnet.

## Common questions

### What is the density of platinum?

21,450 kg/m³, or 21.45 g/cm³.

### Does platinum float?

No. At 21,450 kg/m³ it is denser than water.

### Is platinum magnetic?

Platinum is not ferromagnetic. It is often assumed to be because it is a metal, but most metals are not — only iron, nickel, cobalt and a few alloys are attracted to an ordinary magnet.

## Related pages

- [Does platinum float?](https://atoneplace.net/does-it-float/platinum/)
- [Aluminum](https://atoneplace.net/material/aluminum/)
- [Copper](https://atoneplace.net/material/copper/)
- [Gold](https://atoneplace.net/material/gold/)
- [Titanium](https://atoneplace.net/material/titanium/)
- [Iron](https://atoneplace.net/material/iron/)
- [Lead](https://atoneplace.net/material/lead/)
- [Tungsten](https://atoneplace.net/material/tungsten/)
- [Silver](https://atoneplace.net/material/silver/)

## Sources

- Wikidata — Wikimedia Foundation (https://www.wikidata.org/) [CC0 1.0]