Oiled Emerald Inclusions

First Published: 7 September 2026

Oiled Emerald Inclusions

Explore oiled emerald inclusions in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural emeralds that have undergone fissure filling with colorless oil or resin, documented with information on geographic origin, treatment, lighting conditions, field of view, photographer and published references.

The “gota de aceite” (Spanish for “drop of oil”) effect in this Colombian emerald creates an appearance similar to a topographic map. Sample courtesy Nasser S. Altayyar.
Pyrite (an iron sulfide) is a common mineral inclusion found in emeralds from Colombia and some other sources. The defined crystal faces of this crystal indicate a syngenetic origin. However, pyrite is known to form slightly earlier than emerald in most conditions. Its formation reduces the iron content that is available in the emerald-mineralizing fluid; hence the low iron content of most Colombian emeralds.
Although previously thought to be exclusive to Colombian emeralds, three-phase fluid inclusions can be found in emeralds from many different deposits. In this example, two fluid inclusions appear to be sharing one solid phase (probably halite).
Trapiche emeralds display a striking hexagonal pattern, a reflection of the crystal’s underlying symmetry.
The whomping willow. Iridescent platelets (likely ilmenite), one hexagonal and others irregular in shape, stand out against a verdant background in this Zambian emerald.
Iridescent platelets (likely ilmenite) stand out against a verdant background in this Zambian emerald. Some areas of the platelets have dendritic shapes, while others show hexagonal forms.
A brown, prismatic crystal, possibly tourmaline, is suspended inside of this schist-hosted emerald.
A cluster of crystals, likely mica, of various sizes and shapes is suspended in this Zambian emerald.
A cluster of crystals (likely mica) reaches the surface of this Zambian emerald. When exposed to the gentle heat of the microscope light, oil droplets leaked out at the boundary between the inclusions and the host.
This emerald contained a series of slender two-phase inclusions. Like a genie in a bottle, the bubble (probably carbon dioxide) trapped inside has likely resided there for millions of years.
The Emerald City. Fine tubes form a dramatic skyline in this gem.
Like ribbons, irregular negative crystals decorate the interior of this emerald.

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Emeralds commonly contain surface-reaching fissures that may be filled with colorless oil or resin to reduce their visibility. Microscopic examination may reveal features associated with such filling, including differences in relief, flash effects, trapped bubbles or incomplete filling within fissures.

Oiled Emerald Inclusion Photomicrographs

The Hyperion oiled emerald gallery includes microscopic features documented in natural emeralds recorded as having fissure filling with colorless oil or resin. Each entry identifies the recorded treatment and is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Emerald Treatment

Microscopic examination is an important part of detecting fissure filling in emerald. The appearance of surface-reaching fissures and the materials within them can provide evidence of treatment and help gemologists assess the nature of the filling material.

Hyperion combines inclusion photomicrography with supporting gemological information so that treatment-related features can be compared with documented examples in natural emerald.

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.