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Bright Molybdenite Crystal
SULFIDES; SIMPLE SULFIDES · HEXAGONAL

Molybdenite

MoS2

Hardness
1–1.5
Streak
Gray to grayish-black
Spec. Gravity
4.6–5.1
System
Hexagonal

About

Molybdenite is the most prevalent molybdenum-bearing mineral, and is named after that element. Prior to the discovery of molybdenum as a separate element in 1778 by Karl Wilhelm Scheele, Molybdenite was thought to be Graphite or a lead ore. In fact, the word molybdos means "lead" in ancient Greek.

Molybdenite forms in two distinct crystal polytypes: Molybdenite-2H and Molybdenite-3R. Most Molybdenite is of the 2H type, although it is difficult to distinguish the two without complex analysis, and a distinction is rarely made. Molybdenite occurs in lustrous, metallic-looking crystals that can be easily moved and bent out of shape. It also has perfect cleavage in one direction and is often flaky, allowing thin crystals to be "peeled" similar to the micas.

Crystal Forms & Aggregates

In hexagonal-shaped crystals, often very thin and platy, and sometimes irregular. May also be in thick tabular crystals, and rarely in prismatic tapered crystals. Crystals often have complex growth layers, and can also be bent due to this minerals flexibility. Well-formed hexagonal crystals may also be slightly depressed inwards toward the center. Also micaceous, foliated, scaly, and grainy.

Other ID Marks

Has a greasy feel.

Striking Features

Environment

Uses

Molybdenite the most important ore of molybdenum. It is also an important ore of the rare metal rhenium, which it sometimes contains in small traces. Molybdenite is also used in electronics and is gaining importance as a semiconductor and transistor material.

Noteworthy Localities

Thick crystals of Molybdenite are well-known from Deepwater and Kingsgate, New South Wales, Australia; and highly lustrous crystals came from the Wolfram Camp, near Dimbulah, Queensland, Australia. Large floater crystals of Molybdenite were found in the Hirase mine, Shirakawamura, Gifu Prefecture, Japan; and well-formed crystals came from Bandaksli, Tokke, Telemark, Norway. Molybdenite is found together with gem Emerald in the Carnaiba Mine, Pindobaçu, Bahia, Brazil.

In Canada, some of the most outstanding examples of Molybdenite, in large, well-formed hexagonal crystals on a Quartz matrix come from the Moly Hill mine, near La Motte, Abitibi, Québec. Small crystals are abundant in the Wilberforce area, Haliburton Co., Ontario.

In the U.S., large, lustrous Molybdenite crystals are found in the Crown Point Mine, Railroad Creek, Chelan Co., Washington; and thin plates from the Bingham Canyon Mine, Salt Lake Co., Utah. Small flakes on matrix are common at Climax, Lake Co., Colorado. The largest industrial producer of Molybdenite in North America is the Henderson Mine, near Empire, Clear Creek Co., Colorado, though specimens from this mine are seldom represented in collections.

Common Mineral Associations

Distinguishing Similar Minerals

Due to Molybdenite's unique properties, only Graphite is similar in properties and appearance. In fact, it can be very difficult to distinguish from Graphite. However, Molybdenite does have a higher specific gravity over Graphite, does not smudge like Graphite, and often has a slightly bluer tint.

Photos

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Crystal forms

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Thin Tabular Hexagonal
Thick Tabular Hexagonal