Gemstone Inclusions

The student gemologist, when he first begins to look inside gem-stones under magnification is often amazed at the myriad of included objects he sees there. Tadpole, comma, round, or elliptical bubbles abound as well as fibrous horsetails, cracks, beautiful tiny crystals, blades, feathers and mossy traces of matter. At magnifications of from 10 to 40 times under the microscope it is often possible to recognize inclusions that tell not only what the gem is but where in the world it came from. Tiny actinolite blades in an emerald signal immediately that it was mined in Russia and rtot at the famous mines of Colombia.
These inclusions may have arrived in the gemstone at different times. Some existed before the gemstone was formed and they were swept up and trapped in the developing solid. Even tiny droplets of the liquid from which the crystal formed are sometimes trapped. Some liquid-filled inclusion cavities have tiny gas bubbles that move back and forth in their small prisons as the stone is tilted and other diamond jewelry. Now and then, a mineral species developing from the same liquid as the gemstone leaves its trace as a scatter of bright, little but well-formed crystals peppered through the stone. Often, too, after the gemstone has formed it develops a series of tiny cracks and fissures. These may later be filled by the infiltration of liquids which form new crystalline material to "heal" the breakage. This accounts for the typical "healed" feathers seen in Ceylon sapphires. There are certain significant internal features caused by accidents during growth. Color zoning, sometimes not too obvious without magnification, will appear as definite bands of differing color intensity due to interruptions during growth or slight changes in the content of the supply of material brought to the forming crystal. Prominent hexagonal color zoning is typical of Burmese sapphire.