Inclusions in Gemstones
The term inclusion refers to any imperfection in the appearance of the gemstone. This includes any foreign body enclosed within a gemstone (gas, liquid, and solid), cleavage cracks, and color zoning. Inclusions can weaken the gemstone’s durability or affect the color of the gemstone, in this case inclusions significantly reduce the value of the stone. However, the existence of inclusions is not always bad. For instance, inclusions can provide positive identification and be the proof of originality. In this case, they may increase the value of the gemstone. Furthermore, sometimes inclusions are quite beautiful and make the gemstone more attractive. For instance existence of thin, golden, needlelike crystals of the material rutile change the value of the ordinary quartz. Considering the fact that flawless color stones are very rare, one should be immediately suspicious of any flawless gemstone (especially with today’s technology on fabricating synthetic gemstone). Loupe which is a special type of magnifier that is used by jewellers, can be used to examine a gemstone for any inclusion. Followings are the list of inclusions that are frequently found in gemstone:
- Bubbles: As the name implies this inclusions look like bubbles of different shapes and sizes. It should be noted that very round and nice bubbles are usually indication of synthetic or glass imitated gemstone.
- Cleavage fault: This type is actually a crack in the stone rather than an inclusion. It is often observed in topaz, diamond, feldspar, and kunzite.
- Color zoning is the uneven distribution of gemstone’s color. This inclusion usually occurs as whitish or colorless parallel plates. Color zoning is frequently observed in ruby, sapphire, amethyst, and citrine.
- Dendritic: these are the inclusions that give moss-agate its treelike structure.
- Feather: usually refers to an internal crack
- Halo or Disk-like inclusions: As the name implies, these inclusions look like disk (referred as halos). These inclusions are actually small fractures that result from the growth of zircon crystals inside the host stone. Disk like inclusions are onserved in sapphire and garnet.
- Needlelike: These are very long and thin crystals that resemble needles or thin fibers. These inclusions are frequently observed in tourmaline, ruby, sapphire, and garnet.
- Rain: This inclusion looks like dashed lines resembling falling rain.
- Sheaves: this is the inclusion of the mineral cacoxenite in amethyst gemstone.
- Silk: Thin intersecting needlelike crystals that exhibit a sheen similar to that of silk fabric. This inclusion is frequently seen in ruby and sapphire.
- Solid: This inclusion refers to the presence of a solid crystal or mineral in the host stone.
- Twinning: This inclusion looks like parallel cracks (planes). It is frequently observed in rubies and sapphires which shoes their genuineness.
- Veils: small bubblelike inclusions arranged in layer structures. These inclusions can be wispy, flat or curvaceous.