How do I identify Tungsten?

Tungsten can be identified by its grey color. Look for these key characteristics when examining specimens.

What color is Tungsten?

Tungsten typically appears in grey. Color can vary depending on impurities and formation conditions.

Tungsten

A variety of Minerals

What is Tungsten?

Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite, and wolframite, lending the element its alternate name. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the elements discovered, melting at 3,422 °C (6,192 °F; 3,695 K). It also has the highest boiling point, at 5,555 °C (10,031 °F; 5,828 K). Its density is 19.25 grams per cubic centimetre, comparable with that of uranium and gold, and much higher (about 1.7 times) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material (under standard conditions, when uncombined), making it difficult to work. However, pure single-crystalline tungsten is more ductile and can be cut with a hard-steel hacksaw. Tungsten occurs in many alloys, which have numerous applications, including incandescent light bulb filaments, X-ray tubes, electrodes in gas tungsten arc welding, superalloys, and radiation shielding. Tungsten's hardness and high density make it suitable for military applications in penetrating projectiles. Tungsten compounds are often used as industrial catalysts. Tungsten is the only metal in the third transition series that is known to occur in biomolecules, being found in a few species of bacteria and archaea. However, tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to most forms of animal life.

Uses & Applications

Approximately half of the tungsten is consumed for the production of hard materials – namely tungsten carbide – with the remaining major use being in alloys and steels. Less than 10% is used in other chemical compounds. Because of the high ductile-brittle transition temperature of tungsten, its products are conventionally manufactured through powder metallurgy, spark plasma sintering, chemical vapor deposition, hot isostatic pressing, and thermoplastic routes. A more flexible manufacturing alternative is selective laser melting, which is a form of 3D printing and allows creating complex three-dimensional shapes.

Tungsten Market Value Calculator

Estimate the market value of Tungsten using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Tungsten Localities Map

See where Tungsten is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview

North ZoneCentral RidgeSouth Basin

Key Characteristics

Characteristics of Tungsten

In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. If made very pure, tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily. It is worked by forging, drawing, or extruding but it is more commonly formed by sintering. Of all metals in pure form, tungsten has the highest melting point (3,422 °C, 6,192 °F), lowest vapor pressure (at temperatures above 1,650 °C, 3,000 °F), and the highest tensile strength. Although carbon remains solid at higher temperatures than tungsten, carbon sublimes at atmospheric pressure instead of melting, so it has no melting point. Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong metallic bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel greatly increases its toughness. Tungsten exists in two major crystalline forms: α and β. The former has a body-centered cubic structure and is the more stable form. The structure of the β phase is called A15 cubic; it is metastable, but can coexist with the α phase at ambient conditions owing to non-equilibrium synthesis or stabilization by impurities. Contrary to the α phase which crystallizes in isometric grains, the β form exhibits a columnar habit. The α phase has one third of the electrical resistivity and a much lower superconducting transition temperature TC relative to the β phase: ca. 0.015 K vs. 1–4 K; mixing the two phases allows obtaining intermediate TC values. The TC value can also be raised by alloying tungsten with another metal (e.g. 7.9 K for W-Tc). Such tungsten alloys are sometimes used in low-temperature superconducting circuits.

Formation of Tungsten

Tungsten is found mainly in the minerals wolframite (iron–manganese tungstate (Fe,Mn)WO4, which is a solid solution of the two minerals ferberite FeWO4, and hübnerite MnWO4) and scheelite (calcium tungstate (CaWO4). Other tungsten minerals range in their level of abundance from moderate to very rare, and have almost no economical value.