Tedhadleyite is a extremely rare mercury lead telluride halide mineral known primarily from its type locality in Italy. It typically forms small, equant, colorless crystals associated with other mercury-bearing minerals in hydrothermal settings.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Tedhadleyite

Hardness: 2
Luster: Adamantine
Streak: White
Transparency: Transparent

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Is this tedhadleyite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch tedhadleyite with a known reference. Tedhadleyite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tedhadleyite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Tedhadleyite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: colorless, yellowish-white.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: equant crystals.

Often confused with

Tedhadleyite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Tedhadleyite leaves white, Terlinguaite leaves yellow.

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Often found alongside tedhadleyite

Minerals reported to co-occur with tedhadleyite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: HgHg₂Pb₂Te₂Cl₂
Mohs hardness: 2
Density: 8.8 g/cm³
Colors: Colorless Yellowish-white
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Equant Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Carbonate Rocks

Where rockhounds find tedhadleyite

Classic worldwide localities

Hg-deposit of the Buca della Vena mine, Tuscany, Italy

Field-hunting tip

Look in hydrothermal veins in carbonate rocks country, the host setting where tedhadleyite typically forms. If you start seeing cinnabar, pyrite, quartz in float, you are in the right ground. Field specimens usually show a equant crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tedhadleyite?+

Mohs hardness is 2. It typically shows a adamantine luster. The streak is white. Common colors include colorless, yellowish-white.

Where is tedhadleyite found?+

Notable localities include Hg-deposit of the Buca della Vena mine, Tuscany, Italy.

Is tedhadleyite safe to handle?+

It contains toxic constituents. Contains mercury and lead; avoid contact with skin, ingestion, or inhalation of dust. Handle with care using gloves and store in a sealed container. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tedhadleyite?+

Tedhadleyite is most often confused with Calomel, Terlinguaite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tedhadleyite?+

Tedhadleyite commonly co-occurs with cinnabar, pyrite, quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tedhadleyite form in?+

Tedhadleyite typically forms in hydrothermal veins in carbonate rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tedhadleyite used for?+

Tedhadleyite is used in collector.

Find tedhadleyite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.