Melanophlogite is a rare, silica-based mineral that crystallizes in the cubic system, which is unusual for common SiO₂ species. Collectors prize it for its sharp, small cube-like crystals and distinct, bright blue-white fluorescence under short-wave ultraviolet light.

Hardness

6-6.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareQuartz family

Melanophlogite

Hardness: 6-6.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this melanophlogite?

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 melanophlogite with a known reference. Melanophlogite sits at Mohs 6-6.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Melanophlogite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Melanophlogite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, yellow, brown.
5
Look at form & habit
Crystal system: cubic. Typical habit: pseudocubic crystals, cube-like, pyritohedral faces.

Often confused with

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

How to tell apart: Melanophlogite is noticeably harder (Mohs 6-6.5 vs. 4).

Compare →

Often found alongside melanophlogite

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

All properties

Chemical formula: SiO₂
Mohs hardness: 6-6.5
Density: 2.0-2.1 g/cm³
Colors: Colorless White Yellow Brown
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Pseudocubic Crystals, Cube-like, Pyritohedral Faces
Cleavage: None
Fluorescence: Bright Blue-white Under SW UV
Rarity: Rare
Uses: Collector
Host rock: Sulfur-bearing Gypsum or Clay Deposits
Typical price: $50-500 depending on specimen size and clarity

Where rockhounds find melanophlogite

Classic worldwide localities

Fortullino, Italy
Santa Barbara County, California, USA
Mount Hamilton, California, USA
Mezzano, Italy

Field-hunting tip

Look in sulfur-bearing gypsum or clay deposits country, the host setting where melanophlogite typically forms. If you start seeing sulfur, calcite, gypsum in float, you are in the right ground. Field specimens usually show a pseudocubic crystals, cube-like, pyritohedral faces habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify melanophlogite?+

Mohs hardness is 6-6.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, yellow, brown.

Where is melanophlogite found?+

Notable localities include Fortullino, Italy; Santa Barbara County, California, USA; Mount Hamilton, California, USA; Mezzano, Italy.

How much is melanophlogite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen size and clarity. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like melanophlogite?+

Melanophlogite is most often confused with Analcite, Quartz, Fluorite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with melanophlogite?+

Melanophlogite commonly co-occurs with Sulfur, Calcite, Gypsum, Celestine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does melanophlogite form in?+

Melanophlogite typically forms in sulfur-bearing gypsum or clay deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is melanophlogite used for?+

Melanophlogite is used in collector.

Find melanophlogite on the map

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