Donharrisite is an extremely rare mercury-nickel sulfide found primarily in the mercury mining districts of Texas. It typically occurs as microscopic anhedral grains associated with other rare mercury minerals and is prized by advanced mineral collectors for its unique chemistry.

Hardness

3-3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Donharrisite

Hardness: 3-3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this donharrisite?

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 donharrisite with a known reference. Donharrisite sits at Mohs 3-3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Donharrisite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Donharrisite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, pale yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: anhedral grains.

Often confused with

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

mineral

Cinnabar

Mohs 2-2.5

How to tell apart: Streak differs — Donharrisite leaves black, Cinnabar leaves scarlet; luster reads metallic on Donharrisite and adamantine on Cinnabar.

Often found alongside donharrisite

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

All properties

Chemical formula: Ni₈Hg₃S
Mohs hardness: 3-3.5
Density: 8.8-9.0 g/cm³
Colors: White Pale Yellow
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Mercury Deposits
Typical price: $100-500 per specimen

Where rockhounds find donharrisite

Classic worldwide localities

Mercury district, Terlingua, Texas, USA

Field-hunting tip

Look in hydrothermal mercury deposits country — that is the host setting where donharrisite typically forms. If you start seeing cinnabar, calomel, metacinnabar in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify donharrisite?+

Mohs hardness is 3-3.5. It typically shows a metallic luster. The streak is black. Common colors include white, pale yellow.

Where is donharrisite found?+

Notable localities include Mercury district, Terlingua, Texas, USA.

How much is donharrisite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is donharrisite safe to handle?+

It contains toxic constituents. Contains mercury and nickel, which are toxic. Avoid inhalation of dust and wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like donharrisite?+

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

What minerals are found with donharrisite?+

Donharrisite commonly co-occurs with Cinnabar, Calomel, Metacinnabar. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does donharrisite form in?+

Donharrisite typically forms in hydrothermal mercury deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is donharrisite used for?+

Donharrisite is used in collector.

Find donharrisite on the map

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