Replica watches: look not only at the movement but also at the 'jewels' inside

　　As people's knowledge ofreplica watchgrows, when choosing a replica watch, one should not rely solely on aesthetic preferences but also observe the quality and performance of the movement. In fact, the quality of a movement also depends on how many 'jewels' are inside. In descriptions of mechanical watches, you will often see terms like '21 jewels' or '25 jewels'. Today, let's talk about what these 'jewels' actually are.

　　First of all, the 'jewel' in '25 jewels' refers to the jewels used as bearings in the movement to reduce friction, known as 'functional jewels', not the sparkling diamonds embedded on the watch face or bezel.

　　Some manufacturers, in order to attract attention, have marked the number of decorative diamonds embedded on the surface on the dial; this behaviour is clearly misleading. International standard ISO-1112 stipulates that only functional jewels can be marked on the dial; non-functional jewels, regardless of quantity, are not allowed to be marked.

　　In 1704, natural diamonds were first used in watch movements and patented. Used as bearings, natural diamonds significantly improved the transmission efficiency of the gears, greatly increasing the timekeeping accuracy of the watches and extending their service life.

　　At the time, the use of diamonds in watches was a technical secret. Subsequently, many watch manufacturers began to imitate it, but the selection of materials, drilling, and installation were very difficult and the costs were very high.

　　In 1892, the French invented synthetic diamonds, the main component of which is aluminium oxide, sintered at high temperatures. Various colours such as red, blue, and white are created by adding different colouring agents. When chromium oxide is used as a colouring agent, it becomes the red watch jewel common in watch movements, also known as synthetic ruby.

　　Every industry has its 'rules of the trade'. In the watch industry, the reference to 'jewels' is very specific: 'jewels' are synthetic diamonds, not natural diamonds; if natural diamonds are used in certain parts, it must be specifically noted.

　　The number of jewels in a watch is one of the indicators of its specifications; before the advent of quartz watches, the number of 'jewels' marked was an important indicator of watch quality.

　　Main characteristics of movement functional jewels:

　　1, high hardness (Mohs hardness level 9, second only to the Mohs hardness level 10 of natural diamonds)

　　2, wear-resistant

　　3, good surface roughness

　　4, low coefficient of friction

　　Experiments have proved that when steel components are used together with watch jewels under dry friction conditions, the coefficient of friction typically reaches 0.14; however, under good lubrication conditions, the coefficient of friction can be reduced to 0.01. Therefore, be sure to service your watch every 2-3 years to prevent the lubricant from drying out and thickening, which affects the operation of the movement.

　　Generally speaking, a manual-winding base movement has 17 jewels, which are distributed as follows:

　　Upper and lower centre wheel jewels (2 jewels in total)

　　Upper and lower third wheel jewels (2 jewels in total)

　　Upper and lower fourth wheel jewels (2 jewels in total)

　　Upper and lower escape wheel jewels (2 jewels in total)

　　Upper and lower pallet staff jewels (2 jewels in total)

　　Upper balance shock absorber (2 jewel)

　　Lower balance shock absorber (2 jewel)

　　Pallet fork entry and exit pallets as well as the roller pin (3 jewels in total)