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 — 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
Typical price: n/a

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 — that is 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.

How much is tedhadleyite worth?+

Typical asking prices fall in the range of n/a. Quality, size, and provenance can move individual specimens well outside that range.

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.