The most common sapphire on the market is glass. In fact, it is relatively easy to identify glass. Glass is shaped at high temperature, naturally shrinks after cooling, and the plane is concave inward.
This kind of depression is not easy to find with the naked eye, so a magnifying glass must be used. When using a magnifying glass, you can't focus in a straight line, but focus obliquely, so it is easy to find the concave surface. The concave surface is usually glass. The polishing of precious stones usually achieves a very flat effect.
Another identification method is that there are many kinds of inclusions in glass, the most common one is bubbles, while gems have no bubbles. Bubbles in glass can be found with a magnifying glass of 10 times.
Extended data:
1, Kashmir sapphire: It is a translucent cornflower blue (purple blue) velvet sapphire with a mining history of over 100 years. Authentic Kashmir sapphire is mined due to many factors such as topography and climate, and its output is low. In recent years, there is a lack of high-quality products, but a small number of high-quality products can still be seen in the market.
2. Myanmar sapphire: Very high quality dark blue or sapphire. Under the illumination of artificial light source, some colors are lost and some black appears. Kashmir sapphire has no such blackening characteristics.
3. Thai sapphire: extremely dark blue sapphire, blue-black in the sun (American gem market); Or a very dark blue and slightly velvet gem, not as good as Kashmir sapphire (British gem market). In the United States, this kind of sapphire is also of poor grade.
4. Sri Lankan sapphire: a dull gray-blue to light blue-purple sapphire with obvious luster; When containing a large number of needle-like and flocculent inclusions, the luster is reduced and slightly gray. Colors are often uneven (such as ribbons, stripes, etc.). ) In the history of Sri Lanka, high-quality sapphires have been produced for a long time, ranking among the best (a few can reach the best).