Artificial and Manufactured Gemstones
There are various methods and materials used to manufacture artificial gemstones. A gem may be artificial or manufactured to enhance the beauty of an authentic gem.
Artificial gemstones may simply be coloured glass cut into a gem shape, or they may be a composite of different materials (composite stones). These stones, upon close examination, will reveal swirls of glue under the stone, and the glass will show scratches. Glass stones are simply refractive, while many of the genuine stones are doubly refractive. Many natural minerals may be used to replicate Diamonds. More information may be found at Diamond Imitations.
Composite stones, also called "doublets or triplets"may be made in several ways. All involve layering a gem with different types of material. For example, coloured cememt may be used to bind two stones to darken the colour. Often, glass will used as the lower layer to allow light to pass through a smaller upper layer of gem. Lastly, a synthetic imitation of the gem may be used as the lower layer, the upper layer being authentic.
Manufactured stones, or synthetic stones, have the same chemical composition as authentic stones. Often, they are made of remnants which are melted or powderized before allowing them to recrystallize. Often, these stones may be identified if one is familiar with the nature of the natural crystal. Often, synthetic stones have small air bubbles which are partially coloured. While natural stones may also have bubbles, they are generally clear, the same colour as the gem, and of irregular shapes. Typical synthetic stones are opal, turquoise, and lapis lazuli.
While artificial and manufactured gems may be beautiful and cost- effective, the beauty does not last. Addtionally, genuine stones have the internal "fire" produced by the refrectiveness which cannot be simulated.
Garnet is one of the few natural gemstones not commonly enhanced to improve its color or clarity. However, garnet is often imitated. The laser industry has perfected some synthetic garnets with crystalline structures similar to the natural gem, but different in chemical composition (it's a non-silicate). Synthetic ruby and spinel are also used as a garnet simulant, as is glass, particularly in inexpensive birthstone jewelry.
It can be very difficult to determine real gems from artificial. However, there are some general indications. Mixed gems will have a stable color while true gems often vary in color within the gem. True gems have a particular lustre or glow which comes from within which is never seen in man-made gems. Mixed gems often have visible air bubbles. While true precious stones may have bubbles, the bubbles are of irregular shape and the color of the bubble is identical to that of the gem. If there are stripes of color within a stone, they would be irregular. However, they would not be diagonal. Perhaps the best method to verify (if not very practical) is to immerse the stones into methylene iodide solution. Mixed gems will float while genuine stones will sink.
Some authentic gems may be enhanced using several methods. Find out more here.
