Terlinguacreekite is a rare mercury oxychloride mineral first identified in the famous mercury mines of the Terlingua district in Texas. It typically presents as small, tabular, yellowish-orange crystals or thin crusts associated with other secondary mercury minerals in limestone-hosted hydrothermal veins.
Is this terlinguacreekite?
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 terlinguacreekite with a known reference. Terlinguacreekite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark orange, reddish orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: encrustations.
Often confused with
Terlinguacreekite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Terlinguacreekite and brilliant adamantine to resinous on Eglestonite.
How to tell apart: Streak differs, so Terlinguacreekite leaves yellow, Kleinite leaves sulfur-yellow; luster reads vitreous on Terlinguacreekite and adamantine to greasy on Kleinite.
How to tell apart: Streak differs, so Terlinguacreekite leaves yellow, Terlinguaite leaves lemon-yellow, turning olive-green; luster reads vitreous on Terlinguacreekite and brilliant adamantine on Terlinguaite.
Often found alongside terlinguacreekite
Minerals reported to co-occur with terlinguacreekite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₃Cl₂O₂
- Mohs hardness
- 2-3
- Density
- 9.899 g/cm³
- Colors
- Dark orangeReddish orange
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Encrustations
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral formed by alteration of cinnabar or native mercury as granular crusts
Where rockhounds find terlinguacreekite
Classic worldwide localities
- Perry Pit, Mariposa mine, Terlingua mining district, Brewster County, Texas, USA (type locality)
Field-hunting tip
Where it forms: A secondary mineral formed by alteration of cinnabar or native mercury as granular crusts. If you start seeing calcite, kleinite, calomel in float, you are in the right ground. Typical habit: encrustations. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify terlinguacreekite?+
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What rocks look like terlinguacreekite?+
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Find terlinguacreekite on the map
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