Bangles were made of various types of metals
Traditionally bangles were made of various types of metals like gold, silver, bronze etc. Bangles made from gold are considered the most expensive ones. Another factor that adds to the price of the bangles is the artifacts or the work done further on the metal.
This includes embroidery or small glass pieces or paintings or even small hangings that are attached to the bangles. This may vary anything from glass to metal to lac and even rubber or plastic. The rareness of a color and its unique value also increase the value. Metal bangles are made of aluminum using unique techniques to put new designs and artwork on them. Its include Glass Bangles, Gold bangles, lac bangles, Silver bangles, Plastic bangles, Metal bangles, Artificial lac bangles.
Gems are silicates which can be very stable, hard minerals. Like gemstones, one of the characteristics of a precious metal is its rarity. A few gems are oxides and only one gem, diamond, is composed of a single element, carbon. Often, new names will be created for ordinary sounding minerals which sound prettier or more valuable, such as Moldavite for the green variety of tektites.
It could not be "precious" if it were common! This means that the metal must be malleable, that it can be bent, hammered, or otherwise shaped. Two other characteristics are also important. There are also many gemstones that are not true minerals, but which are gemstone varieties of recognized minerals.
All gemstones have some characteristics
Many gemstones are used in even the most expensive jewellery depending on the brand name of the designer, fashion trends, market supply, treatments etc. Others are too common and are given a semi-precious status. Most gemstones have good hardness and a high index of refraction.
All gemstones have some characteristics falling short of perfection though; even the seemingly perfect Diamond has four directions of cleavage. Since quartz is everywhere especially in common dirt and dust. Any material that is softer may be scratched during ordinary wear. Nevertheless, diamonds, rubies, sapphires and emeralds still have a reputation that exceeds those of other gemstones.