Tugarinovite is a rare molybdenum oxide mineral that typically occurs as small inclusions or grains within hydrothermal vein deposits. It is often challenging to identify in the field due to its small size and similarity to other opaque oxides like rutile or cassiterite, often requiring chemical analysis for verification.
Is this tugarinovite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch tugarinovite with a known reference. Tugarinovite sits at Mohs 4.6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish gray.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to metallic.
- 4Match the color rangeCompare against the expected color range: violet brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, tabular, twinning common.
Often confused with
Tugarinovite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Cassiterite is the harder of the two (Mohs 6-7 vs. 4.6); streak differs, so Tugarinovite leaves greenish gray, Cassiterite leaves white, pale brown, pale gray; luster reads greasy to metallic on Tugarinovite and adamantine to adamantine metallic, splendent; may be greasy on fractures on Cassiterite.
How to tell apart: Rutile is the harder of the two (Mohs 6-6.5 vs. 4.6); streak differs, so Tugarinovite leaves greenish gray, Rutile leaves pale brown, yellowish brown; gray, greenish black with high nb–ta; luster reads greasy to metallic on Tugarinovite and adamantine to submetallic on Rutile.
How to tell apart: Tugarinovite is noticeably harder (Mohs 4.6 vs. 3-4); streak differs, so Tugarinovite leaves greenish gray, Molybdite leaves white; luster reads greasy to metallic on Tugarinovite and adamantine on Molybdite.
Often found alongside tugarinovite
Minerals reported to co-occur with tugarinovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MoO₂
- Mohs hardness
- 4.6
- Density
- 6.58 g/cm³
- Colors
- Violet brown
- Streak
- Greenish gray
- Luster
- Greasy to metallic
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, tabular, twinning common
- Cleavage
- Distinct on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed as a primary mineral, by metasomatism in a reducing environment deficient in sulfur
Where rockhounds find tugarinovite
Classic worldwide localities
- Lenskoye Mo–U deposit, Amur district, eastern Siberia, Russia
Field-hunting tip
Where it forms: Formed as a primary mineral, by metasomatism in a reducing environment deficient in sulfur. If you start seeing uraninite, molybdenite, galena in float, you are in the right ground. Typical habit: prismatic, tabular, twinning common. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tugarinovite?+
Where is tugarinovite found?+
What rocks look like tugarinovite?+
What minerals are found with tugarinovite?+
What kind of rock does tugarinovite form in?+
What is tugarinovite used for?+
Find tugarinovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
