Skip to main content

Carat

Diamonds have weight and they are measured in terms of carat(cts). Diamonds can also be measured in grams or kilogram but carat is the term used because of the history related to it.

History:
    All seeds of carob tree weigh the same. Each seed weigh 200 milligram (mg) exactly and they are used as standard to measure the weight of gemstones and pearls because there were no machines in the past. They called each seed weight as a carat which is 200mg and carat term is very widely used for measuring the weight of diamonds.
    1cts       = 200mg
    5cts       = 1g
    100cts   = 20g
    3106cts = 621.2g world's largest diamond ever recorded. So now you understand that single diamond do not come in kgs.

Carat and its importance:
    Among the 4c's of diamond, the value is highly dependent on carat. The bigger the weight- the higher the price. They start from 0.01, 0.02, 0.03, 0.04, ......., 0.61, 0.62, ........, 0.99, 1.00, 1.01, ........, 1.99, 2.00, 2.01, ......., etc. If the diamond price of 0.37cts is $1670 then similarly 0.38cts is $1700 and 0.39 is $1730. A difference of $30 for every 0.01cts more weight.
    Diamonds also have size ranges. Example 0.30 to 0.39 is a size range and 0.40-0.49 is next size range. Lets say diamond weighs 0.40cts and its price will no more be $30 more than 0.39cts. It can be $90 more than 0.39cts because it falls in the next size range. If you observe the price difference between 0.39cts and 0.40cts is $90 for 0.01cts. This is how it works. If the diamond falls in the next size range then the diamond price increases multiple times. You can never increase weight of diamond but you can only save the weight in manufacturing. 0.40cts is a break size which is start of a new size range. Once you hit the break size or next size range the price value of diamond jumps multiple times.
    Almost all diamond industry follow rapaport for diamond rough valuation and polish price. Rapaport have all size ranges and weights starting form 0.01 to 10.00cts+. Above 10.00cts is considered as special diamonds. Lets see how we can use the rapaport to calculate the price of diamond

What happens if we overpolish the diamond in manufacturing?
Example 1: Diamond estimated for 1.02cts H VS2 EX at $5431. The diamond moved into manufacturing and the polisher by mistake polish too much more on the facet and the diamond end up as 1.01 H VS2 EX at $5378. Loss here is $53
Example 2: Diamond estimated for 1.02cts H VS2 EX at $5431. The diamond moved into manufacturing and the polisher by mistake polish too much more on the facet and the diamond end up as 1.00 H VS2 EX at $5325. Loss here is $106
Example 3: Diamond estimated for 1.02cts H VS2 EX at $5431. The diamond moved into manufacturing and the polisher by mistake polish too much more on the facet and the diamond end up as 0.99 H VS2 EX at $4009. Loss here is $1422

    Also check the value loss of diamond if there is drop in color, clarity, cut and fluorescence and compare with carat when you loose a break size. Then you will observe loosing break size is a huge damage. No manufacturer will ever want to loose break sizes.

How to measure weight of diamonds?
    Today we have many weighing scales available in the market- Mettler scale, sartorius, etc. They can measure upto 4 digits after decimal.

Comments

Popular posts from this blog

Tools and equipment

Crafting of diamond need tools and equipment to polish a rough diamond to a jewelry diamond starting from import into factory to export. Technology has grown enormously in 21st century where you put a sawn (cut) diamond in a machine and get jewelry diamond in few hours. Lets start from the history.      History:      Diamonds were used to cut diamond rubbing against each other. In 15th century, tools were invented and among them Scaif is the best invention by Lodewyk Van Berken. Scaif is a polishing wheel infused with a mixture of olive oil and diamond dust. Diamonds are put in contact to scaif which rotates at 3000rpm. This helps polishing the diamond. The time taken to polish has drastically reduced at higher quality. Polishing tangs have been introduced to hold diamond when you put the diamond in contact to scaif.     TOOLS & EQUIPMENT       1. Galaxy machine:     Product of Sarin that makes the diamond surface tran...

Window polisher

Polisher deals with the rough diamond. Follow planners' pen marking to polish and return back to the planner/ section monitor/ section supervisor. This task is performed because of following reasons: Surface of the diamond is frosted or coated Inclusions are clearly visible though the surface is clear Understand depth of inclusions To confirm inclusion type or nature To confirm the clarity Responsibilities: Check every parcel have diamond when receiving parcels from stock controller Check weight of diamond in weighing scale and confirm if it matches with the current weight mentioned in the parcel Be sure that you fully understand pen marking by the planners Consumables, tools and equipment are available and in good condition Opening the scaif should be done just before shift end so that you are ready for tomorrow Cover your scaif and oil your tang when going for weekend or holidays Ensure your polishing mill is clean and tidy before knocking off for the day Scaif have to be balance...

Bottom polisher

Follows finishing supervisor instructions written in parcel to polish and return back to the finishing supervisor. They will confirm if polisher polished according to the instructions and the diamond need anything more to be polished and then send it to the section QC for polish and symmetry quality check. This task is performed because of following reasons: Ensure parameters, polish and symmetry are met as per rough estimations Finalize the bottom Responsibilities: Check every parcel have diamond when receiving parcels from stock controller Check weight of diamond in weighing scale and confirm if it matches with the current weight mentioned in the parcel Be sure that you fully understand finishing supervisor instructions written in parcel Consumables, tools and equipment are available and in good condition Opening the scaif should be done just before shift end so that you are ready for tomorrow Cover your scaif and oil your tang when going for weekend or holidays Ensure your polis...