Natural Ruby Inclusions

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

Prior to heat treatment, most rubies from Mong Hsu, Myanmar display a deep blue core surrounded by layers of cottony diaspore silk, as shown here in classic form.
Solid inclusions are a relatively rare sight in rubies from Myanmar’s Mong Hsu area. This perfectly formed hexagonal prism cut through on the surface, not unexpectedly, turned out to be fluorapatite, as proven by micro Raman.
Solid inclusions are a relatively rare sight in rubies from Myanmar’s Mong Hsu area. This perfectly formed hexagonal prism cut through on the surface, not unexpectedly, turned out to be fluorapatite, as proven by micro Raman.
During a crystal’s growth, conditions may change. The result is reflected by growth features such as zoning, twinning, dislocations, etc. These changes may also influence events that occur after the growth, such as exsolution (the unmixing of a solid solution). In this Mozambique ruby, we can see a zoned cloud of fine exsolved particles that shifts dramatically to much larger exsolved needles/plates.
During a crystal’s growth, conditions may change. The result is reflected by growth features such as zoning, twinning, dislocations, etc. These changes may also influence events that occur after the growth, such as exsolution (the unmixing of a solid solution). In this Mozambique ruby, we can see a zoned cloud of fine exsolved particles that shifts dramatically to much larger exsolved needles/plates.
Undissolved rutile silk is strewn like confetti beneath the table facet of this Mozambique ruby. This is seen when looking down the c axis.
This ruby contained dozens of black crystal flakes strewn randomly across the stone; We used micro Raman to analyze one that broke the surface, revealing it to be graphite. Graphite has been found in many rubies across the Himalayan arc.
We noticed transparent crystals cut through on the surface of this ruby from Mozambique’s Montepuez region. Micro Raman revealed the lower luster crystal to be pargasite (amphibole), while the two higher relief crystals tested as spinel. Because their luster is even higher the surrounding ruby, their refractive index is above 1.77. This suggests that rather than being pure spinel (MgAl2O4), they are probably mixed with another species, such as chromite (Fe2+Cr3+2O4). Chromite has an RI of 2.08 to 2.16.
Complex angular growth zoning in a ruby from Mozambique’s Montepuez region.
The different lusters of this crystal cut through on the surface of a Mozambique ruby reveal that the inclusion is actually made of two different components. Micro Raman spectroscopy confirmed the identity of the higher luster (brighter) area as chromite and the lower luster (darker) area as pargasite.
A light dusting of rutile silk in this 5.59 ct ruby can be spotted at high magnification. The features pictured provide evidence that this gem is unheated and hails from Myanmar’s (Burma’s) storied Mogok region. This inclusion scene is a unique identifying feature of the gem.
Mozambique ruby is one of the most important stones on the market today. This one contains a beautiful metallic crystal with nice surface markings.

Natural ruby inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, color zoning and other features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying ruby, understanding its geological history, recognizing treatment and, in some cases, determining geographic origin.

Natural Ruby Inclusion Photomicrographs

The Hyperion natural ruby gallery includes microscopic features found in rubies from major deposits around the world. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Natural Ruby

Inclusions are an important part of ruby identification. Their form, composition, orientation and alteration can help gemologists distinguish natural ruby from synthetic material, recognize evidence of heat treatment, and study the geological environment in which the ruby formed.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from known ruby deposits.

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.

Search the Complete Hyperion Database