Guide To Buying Diamonds

The 4cs of a diamond

This range is very strict and combines the best in brilliance and fire. Technically, the head of the class.

This range is also of great beauty yet slightly more flexible regarding percentages. Many experts prefer the appearance of this range to Ideal.

This range is balanced between precise proportions and price considerations. Viewed by many as the best overall value in beauty and price.

when a diamond is cut to proper proportions, light is reflected from one facet to another and then dispersed through the top of the stone. Within the Well Cut standards sub categories are Ideal, Excellent, Very Good and Good.

When the cut of a diamond is too deep, some light escapes through the opposite side of the pavilion.

When the cut of a diamond is too shallow, light escapes through the pavilion before it can be reflected.

The cut, or proportions, of a diamond is measured in percentages relative to the diameter of its girdle. The girdle diameter of each diamond is always considered 100%. Example: The girdle of a diamond measures 10 millimeters (100%). The table measures 5.6 millimeters. The total depth measurement is 6.1 millimeters. The diamond would be described as having a table of 56% and a depth of 61%. The table and depth percentages are the key to determining good proportions.


The cut of a diamond refers to its proportions. Of the 4C’s, the cut is the aspect most directly influenced by man. The other three are dictated by nature.

Quite often the cut of a diamond is confused with its shape. Diamonds are cut into various shapes depending upon the original form of the uncut diamond, which is referred to as rough. Whatever the shape, a well-cut diamond is better able to reflect light.

A diamond’s ability to reflect light determines its display of fire and brilliance. Diamonds are usually cut with 58 facets, or separate flat surfaces. These facets follow a mathematical formula and are placed at precise angles in relation to each other. This relationship is designed to maximize the amount of light reflected through the diamond and to increase its beauty.

Different shapes of diamonds
Round Brilliant Princess Cut
Emerald Cut Marquise
Radiant Pear Shape
Heart Shape Oval
Asscher Trillion/Triangle

Most people compare carat weight to size. The larger the diamond the more it weighs. The weight of a diamond is expressed in carats. The word carat originated from the carob tree or Ceratonia siliqua. The tiny seeds of this tree are well known for their uniformity and consistent weight. Traditionally diamonds and gemstones were weighed against these seeds until the system was standardized, and one carat was fixed at 0.2 grams. One carat is divided into 100 points. A diamond weighing one quarter of a carat can also be described as weighing 25 points or 0.25 carats. Points are generally not used to describe weights over one carat.

  • When we speak of a diamond’s clarity, we are referring to the presence of identifying characteristics on (blemishes) and within (inclusions) the stone.
  • If you think about the incredible amount of pressure it takes to create a diamond and the fact that natural diamonds are not grown in a sterile laboratory, it’s no surprise that most diamonds have flaws.
  • Basically there are two types of flaws: inclusions and blemishes. Inclusions refer to internal flaws and blemishes refer to surface flaws. However, in the diamond grades listed below, you’ll note that none of the grades include the term “blemish” — for the purposes of grading diamonds, all flaws are called “inclusions.”
  • Inclusions include flaws such as air bubbles, cracks, and non-diamond minerals found in the diamond. Blemishes include scratches, pits, and chips. Some blemishes occur during the cutting processes (most often at the girdle). Diamonds with no or few inclusions and blemishes are more highly valued than those with less clarity because they are rarer.
  • Diamonds are graded for clarity under 10x loupe magnification. Grades range from Flawless (diamonds which are completely free of blemishes and inclusions), to Included 3 (diamonds which possess large, heavy blemishes and inclusions that are visible to the naked eye).
  • IF Internally Flawless: No internal flaws. Very rare.
  • VVS1-VVS2 Very Very Slightly Included (two grades). Minute inclusions very difficult to detect under 10x magnification by a trained gemologist. We do not recommend any diamond grades below this grade from and above 0.50 CT.
  • VS1-VS2 Very Slightly Included (two grades). Minute inclusions seen only with difficulty under 10x magnification. We do not recommend any diamond grades below this grade.
  • SI1-SI2 Slightly Included (two grades). Minute inclusions more easily detected under 10x magnification.
  • I1-I2-I3 Included (three grades). Inclusions visible under 10x magnification AS WELL AS to the human eye.
Metals we recommend for diamond jewellery
18kt white / yellow gold:
  • Gold is a rare metallic element with a melting point of 1064 degrees centigrade and a boiling point of 2808 degrees centigrade. Its chemical symbol, Au, is short for the Latin word for gold, ‘Aurum’, which literally means ‘Glowing Dawn’. It has several properties that have made it very useful to mankind over the years, notably its excellent conductive properties and its inability to react with water or oxygen.

Why is gold measured in carats?

  • This stems back to ancient times in the Mediterranean /Middle East, when a carat became used as a measure of the purity of gold alloys. The purity of gold is now measured also in terms if fineness, i.e parts per thousand. Thus 18 carats is 18/24th of 1000 parts = 750 fineness.
  • The 18k white gold at RPS is 75% gold, alloyed with 25% white metals to produce a white metal with a slight yellow color. To enhance the whiteness, almost all white gold is plated with rhodium, an extremely hard and shiny white metal in the platinum group. Depending on the amount of wear to a piece of jewellery, over time this rhodium plating may wear off, revealing the original metal color. Re-plating is a simple process that can be done to restore your jewellery’s whiteness if needed.
  • Platinum’s origins in jewellery go back nearly 2,000 years to the pre-Columbian Indian civilisations of South America. Its modern tradition begins with the European court jewellers of the 18th century and extends to the exquisite creations of the great jewellers of the Edwardian era and the Art Deco period. Today, it is used by jewellers around the world with skill and inspiration to create dazzling innovations in jewellery technique and design.
  • Platinum jewellery is rarely manufactured from 100 per cent platinum because the pure metal is too soft to withstand the rigours of daily wear. Most is typically produced using Platinum of 85 to 95 per cent purity, alloyed with small amounts of other metals to increase its hardness. The platinum purity or “fineness” is nearly always measured in parts per thousand (ppt). A hallmark showing “Pt950” certifies that the metal is composed of 950 ppt (95 per cent) platinum and 50 ppt (5 per cent) other metals.
  • Platinum represents excellent value for money. The price may be higher than similar items in gold but platinum is pure, rare, enduring, beautiful, luxurious, classic, and the perfect host for diamonds, precious qualities that make it worth paying that little bit extra for.
Platinum-white gold
  • Platinum is naturally white whereas white gold is artificially coloured by adding other metals and is also frequently rhodium. The plating can wear off, however, and the colour underneath is often not as white as that of platinum. Platinum jewellery is non-allergenic, comaptible with all skin types.
  • Over time platinum develops a natural patina, which many people find just as attractive as a polished finished, but this does not represent any material loss and platinum rings will not thin with age. It is still important to care for platinum jewellery.
Jewellery care
  • Remove all jewellery when doing manual work
  • Clean from time to time using a soft brush in soapy water
  • Dry using soft, clean, non-abrasive cloth
  • Gently rub to maximise the shine
  • Never use abrasive cleaners
  • Store carefully in a safe place, seperate from other items

We offer an inexpensive re-polishing service,for all our clients and recommend to get wedding rings polished,every year

  • There are three compulsory hallmarks applied to precious metals as a quality control: a sponsor’s (maker’s) mark, a fineness mark, and an assay office mark. These marks establish the origin and fineness of the precious metal and ensures it has been accurately and independently tested.
  • There are few exemptions to the hallmarking laws. One exemption is by weight; compulsory hallmarks are not needed on gold under 1g, silver under 7.78g and platinum under 0.5g. Also, the UK is required by the European Court of Justice to accept other European national hallmarks as sufficient hallmarking, providing those hallmarks represent an equivalent guarantee of quality.