Mozambique Ruby Inclusions

First Published: 7 September 2026

Mozambique Ruby Inclusions

Explore Mozambique ruby inclusions in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural rubies from Mozambique, documented with information on treatment, lighting conditions, field of view, photographer and published references.

Although somewhat uncommon, vague blue color zones are sometimes found in Mozambique rubies. Dealers will often heat-treat such stones to remove the blue color.
Dart-like exsolved rutile silk (high relief) with daughter crystals (lower relief) at the broad ends is a common feature of Mozambique rubies. Heat treatment often produces a breakdown of the daughter crystals, producing white spots or bubbles within the daughter.
Some inclusions in Mozambique rubies are thermally sensitive. Here we find small crystals that have melted. The melted crystal (glass) occupies less volume than the original crystal, resulting in a frozen contraction bubble. A small fingerprint surrounds each melted crystal.
Amphibole rods are a common feature of Mozambique rubies, not surprising since the ruby formed in amphibolite (a metamorphic rock consisting mainly of amphiboles) matrix.
Rutile silk (high relief) with daughter crystals (lower relief) at the broad ends is a common feature of Mozambique rubies. Heat treatment often produces a breakdown of the daughter crystals, producing white spots or bubbles within the daughter.
Glass filling in a surface-reaching cavity in a Mozambique ruby. Note the conchoidal fracture on the glass filling.
A mica crystal with a lovely “rosette” surrounding it graces the interior of this untreated Mozambique ruby from the Montepuez area.
A mica crystal with a lovely “rosette” surrounding it graces the interior of this untreated Mozambique ruby from the Montepuez area.
This Mozambique ruby has been heat treated, causing an included crystal to melt. The resulting glass occupies less space than the previous crystal, resulting in a frozen gas bubble.
Included crystals in a ruby from Montepuez, Mozambique.
When a gem is heat treated, solid inclusions may melt. This photo illustrates two different examples. In the foreground a crystal has melted and cooled into a glass. Because the glass takes up less volume than the earlier crystal, the difference results in a bubble in the glass. Looking further in the background we can see small blue dots. These are the remnants of rutile silk. Heat treatment alters the rutile, sending titanium into solid solution in the corundum. The result is blue “ink spots” surrounding the partially dissolved rutile.
Mozambique rubies are recovered from an iron-rich soil, which stains the surface-reaching fissures orange. Heat treatment at just 350°C converts the yellowish limonite, which consists of α-FeO(OH), to reddish hematite, which consists of α-Fe2O3. Unfortunately the strong body color of ruby makes it impossible to see this conversion by color alone, but micro-Raman spectroscopy can sometimes detect the change. Heat treatment also causes these naturally-stained fissures to become white and even begin healing into fingerprints.

Mozambique ruby inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, growth features and other internal features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying ruby and evaluating a possible Mozambique origin.

Mozambique Ruby Inclusion Photomicrographs

The Hyperion Mozambique ruby gallery includes microscopic features documented in rubies from Mozambique. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Mozambique Ruby

Inclusions are an important part of geographic origin determination in ruby. Their form, composition, orientation and associations can provide evidence that, when considered together with other gemological properties, may support or contradict a Mozambique origin.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from Mozambique rubies.

About Hyperion

Hyperion is the Lotus Gemology searchable inclusion database. It allows users to browse gemstone inclusions by gem type, geographic origin, treatment and keyword.

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