The Heaviest Metal in the World: Osmium and the Density Ranking

Q: What is the heaviest metal in the world?

Osmium, with a density of 22.59 g/cm³ (0.816 lb/in³), is the heaviest and densest metal in the world. Iridium follows closely at 22.56 g/cm³, then platinum at 21.45 g/cm³.

Q: Is osmium heavier than gold?

Yes, clearly. Osmium has a density of 22.59 g/cm³, gold 19.32 g/cm³. A piece of osmium weighs about 17 percent more than a piece of gold of the same size.

Q: Is osmium heavier than tungsten?

Yes. Tungsten has a density of 19.25 g/cm³, slightly below gold; osmium is 22.59 g/cm³. Tungsten is often called the heaviest common metal, but osmium, iridium, platinum, rhenium and gold are all denser.

Q: What is the difference between heavy and dense?

Strictly speaking the correct term is dense. Density is mass per volume, measured in grams per cubic centimetre. Colloquially, the heaviest metal means the same thing: the metal that weighs the most at the same size.

Q: What is the rarest metal on Earth?

Osmium is considered the rarest stable element on Earth. It occurs only as a companion of platinum and is recovered in very small quantities as a by-product of platinum mining.

Q: How much does a cubic centimetre of osmium weigh?

About 22.6 grams. A cube with 10 cm edges, one litre, would weigh roughly 22.6 kilograms, just under 50 pounds.

The ranking

The densest metals compared

Density tells you how much one cubic centimetre of a material weighs. The higher the value, the heavier a piece of the same size feels in your hand. All figures at room temperature.

Rank	Metal	Density	Weight of a 1 cm³ cube
1	Osmium	22.59 g/cm³	≈ 22.6 g
2	Iridium	22.56 g/cm³	≈ 22.6 g
3	Platinum	21.45 g/cm³	≈ 21.5 g
4	Rhenium	21.02 g/cm³	≈ 21.0 g
5	Neptunium	20.45 g/cm³	≈ 20.5 g
6	Plutonium	19.82 g/cm³	≈ 19.8 g
7	Gold	19.32 g/cm³	≈ 19.3 g
8	Tungsten	19.25 g/cm³	≈ 19.3 g
9	Uranium	18.95 g/cm³	≈ 19.0 g
10	Tantalum	16.65 g/cm³	≈ 16.7 g
11	Mercury	13.53 g/cm³	≈ 13.5 g
12	Rhodium	12.41 g/cm³	≈ 12.4 g
13	Lead	11.34 g/cm³	≈ 11.3 g
14	Silver	10.49 g/cm³	≈ 10.5 g
15	Copper	8.96 g/cm³	≈ 9.0 g
16	Iron	7.87 g/cm³	≈ 7.9 g
17	Aluminium	2.70 g/cm³	≈ 2.7 g

Lead is the everyday byword for heavy, yet it only ranks 13th. Tungsten, often called the heaviest common metal, sits just below gold. A cube of osmium weighs almost twice as much as lead and roughly eight times as much as aluminium at the same size.

Heavy or dense – what is the difference?

Strictly speaking, the correct word is dense. Weight depends on quantity: a kilogram of aluminium weighs exactly as much as a kilogram of osmium. Density, on the other hand, describes how much mass is packed into a given volume, expressed in grams per cubic centimetre.

Anyone searching for the “heaviest metal” almost always means exactly that: the metal that weighs the most at the same size. And that is osmium. The difference only shows when you put two pieces side by side: an aluminium cube the size of a sugar lump weighs just under three grams, the same cube made of osmium almost 23.

Calling osmium the densest element is equally correct, because no other element in the periodic table reaches its value. More on its properties under What is osmium.

Crystal structure of osmium under high magnification

A narrow lead

Osmium or iridium – which is really ahead?

Between osmium at 22.59 g/cm³ and iridium at 22.56 g/cm³ lie three hundredths. That is so little that for decades the two metals took turns as the densest element, depending on the measurement method and the sample used.

X-ray diffraction settled the question: from the crystal structure and the atomic mass, the density can be calculated without impurities or trapped air distorting the result. By that method osmium comes out ahead, if only just. In practice both metals are about equally heavy, and when you have to point at a single element, you point at osmium.

The reason for the top spot lies in the atom itself. Osmium combines a high atomic mass with a comparatively small atomic radius, an effect of the relativistic contraction of its inner electron shells. Its atoms are therefore packed exceptionally tightly.

More superlatives

Not just the densest metal

Densest element

22.59 g/cm³ – no other element in the periodic table reaches this value.

Rarest stable metal

Osmium occurs only as a companion of platinum and is recovered in tiny quantities during platinum mining.

Hardest of the platinum group

Osmium is the hardest of the six platinum metals and at the same time very brittle.

Forgery-proof

The crystalline form carries a unique surface structure that cannot be reproduced.

The rarest metal on Earth

Osmium is not only the densest but also the rarest stable element on Earth. It never occurs on its own, only as a companion of platinum. During platinum mining it is recovered in very small quantities as a by-product, and only a fraction of that can be converted into the crystalline form.

This combination of highest density and extreme rarity explains why osmium has been regarded as a tangible asset since the crystalline form was first issued in 2017. The current price is €2,301 per gram (as of 11 September 2026), about €71,568 per troy ounce or €2,300,980 per kilogram. How that price has developed is shown on the osmium price page with a daily updated chart.

If you want to feel the density for yourself, the osmium cube is the usual choice: it makes the difference to gold or lead immediately tangible.

Crystalline osmium cube with a blue-silver shimmer

Frequently asked

Heaviest metal – frequently asked questions

What is the heaviest metal in the world?

Osmium, with a density of 22.59 g/cm³ (0.816 lb/in³). Iridium follows closely at 22.56 g/cm³, then platinum at 21.45 g/cm³.

What is the densest metal?

Osmium is the densest metal and the densest naturally occurring element, at 22.59 grams per cubic centimetre.

Is osmium heavier than gold?

Yes, clearly. Gold is 19.32 g/cm³. A piece of osmium weighs about 17 percent more than a piece of gold of the same size.

Is osmium heavier than tungsten?

Yes. Tungsten is 19.25 g/cm³, slightly below gold. Osmium, iridium, platinum, rhenium and gold are all denser than tungsten.

What is the difference between heavy and dense?

Strictly speaking the correct term is dense: density is mass per volume. Colloquially, “the heaviest metal” means the same thing, the metal that weighs the most at the same size.

What is the rarest metal on Earth?

Osmium is considered the rarest stable element. It occurs only as a companion of platinum and is recovered in very small quantities as a by-product.

How much does a cubic centimetre of osmium weigh?

About 22.6 grams. A 10 cm cube, one litre, would weigh roughly 22.6 kilograms, just under 50 pounds.

Densities according to standard reference values at room temperature. The content of this page is informational and does not constitute investment advice.

Read on

The heaviest metal in the world is osmium