Jewellery Care
General Tips
When storing jewellery,
- Keep your jewellery separately.
- Avoid keeping the jewellery together as they may scratch against each other.
- Avoid squeezing big jewellery into a small box.
- Avoid placing jewellery close to any chemicals.
When wearing jewellery,
- Refrain from doing heavy household chores or gardening.
- Refrain from playing sports.
- Refrain from getting too close to a fireplace.
- Refrain from touching the jewellery and/or gemstones with your finger.
- Avoid chemical contact such as perfume, cosmetics, etc, with your jewellery.
When cleaning jewellery,
- Pearls and Corals: Use a clean, soft and slightly damp cloth that is not chemically treated.
- Gemstones (Diamond, Emerald, Ruby, Sapphire, etc): Wash with warm diluted soap water and rinse with clean water. Dry it with cool air using a hair-dryer.
Diamond
The value of diamond is determined by four distinct factors namely cut, colour, clarity and carat.
Cut
How a diamond has been cut, polished and to what proportions, are important factors determining the life, brilliance and lustre of the diamond. Cuts are graded as Ideal, Excellent, Very Good, Good, Fair or Poor. Ideal cuts typically have more fire, but less brilliance than the best non-ideal cut stones. The brilliant or round cut is the most popular. Other exquisite cuts including the marquise-, pear-, oval-, emerald-, princess- and heart-shaped cuts are also highly prized.
Colour
Colour is graded by comparison to a master set of stones under standardised artificial white light, or Northern Daylight. Most diamonds vary in shade from colourless to yellow. The colour of diamond range from D (colourless, excellent white) to Z (yellowish) The colour of top quality diamonds range from D-F, followed by commercially white diamonds G-H. Diamonds also come in fancy colours such as yellow, orange, pink, blue, green and even black.
Clarity
In order to grade the clarity of a diamond, it is necessary to ascertain the number and nature of inclusions present in the stone, as well as their size and position. This analysis is carried out using the microscope and a loupe 10x under the experienced eye of laboratory gemmologists; the fewer the inclusions, the rarer the stone. A diamond is said to be “Internally Flawless” when it presents no internal defect under 10 x magnifications.
Carat
The weight of a diamond is expressed in carats. 1carat = 0.2 gram. A larger diamond is rare and has a higher value per carat.
Emerald
Emeralds require special care as they are prone to chipping, change of clarity and colour lightening. The lower the quality and the more wear the stones are subjected to, the more likely these problems will arise.
Keep emeralds away from heat and sunlight as these may cause fillers to evaporate quickly.
It is not advisable to clean emeralds using ultrasonic and/or soak them as most emeralds have oil or epoxy fracture-filings, which may be dissolved over time by soap or cleaning solutions. Emeralds can be cleaned using a soapy cloth, rinsed with cool water and dry with a lint-free cloth, or by spraying the stones with a window cleaner and wiping them off with a cloth. A toothpick or unwaxed dental floss may be used to remove dirt on the stones, which cannot be removed with a cloth.
If dirt still remains, have the stones professionally cleaned by a jeweller. Never soak emeralds in alcohol, acetone or paint thinner, which will rapidly dissolve oil fillings.
Ruby and Sapphire
Rubies and sapphires have a hardness and resistance to chemicals that make them suitable for everyday wear. They can be soaked in lukewarm soapy water using a mild liquid detergent. However, it is advisable to have them professionally cleaned by steam cleansers and/or ultrasonic (cleaning machines that shake dirt loose with a vibrating detergent solution using high-frequency sound waves). The following are a few exceptions where rubies and sapphires should avoid being cleaned by steam cleansers or ultrasonic:
- Badly flawed stones with fractures
- Black star sapphires
- Rubies with glass-filled cavities
- Oiled and/or dyed stones
South Sea Pearl
Every pearl is unique and an intuitive selection is based on what is beautiful to the eye of the beholder. The following qualities of South Sea Pearls define their value, and a knowledge of these will aid the selection process.
Lustre
The lustre is the defining virtue of beauty and therefore value. The lustre of pearl refers to light reflecting from the surface and also how it glows from within. Lustre ranges from the bright and sprightly to the warm and alluring. The lustre of South Sea Pearls is natural and should never be chemically modified or enhanced.
Size
The larger the pearl, the scarcer it is. Australian South Sea Pearls are largest in the world.
Measured across the smallest diameter, sizes range from 8mm to an extremely rare 18mm. Only
the South Sea’s Mother-of-Pearl shell can create quality pearls of such size.
Shape
Shape of pearls are categorised either as ‘Classical’ or ‘Baroque’. Perfectly round pearls are the
scarcest and are valued accordingly. Baroque pearls with their unique shapes are increasingly
sought after.
Surface
The more flawless the pearl is, the higher the value. Markings on pearls are part of the unique and
individualising elements of every pearl. Only one oyster in a million may produce a perfect, flawless
pearl.
Colour
South Sea Pearls come in an array of natural colours, namely Peacock-green, Golden and Classic
Silver-white. The choice of colour is a matter of personal preference. While the colour is irrelevant to
a pearl’s intrinsic value, popularity and demand for a colour has an impact on the price.
Jade
Jade is the signature gemstone of On Cheong. It comes in a luminous array of precious hues from green, red, golden, lavender to white. Each piece of jade varies with its colour, translucency/texture, inclusions, quality of cut and artwork. There are different grades of jade. They are A-jade, B-jade and C-jade respectively.
Natural jadeite or A-jade refers to natural jadeite without any treatment. A-jade of excellent colour, tone, translucency, texture and cut are most valuable.
B-jade refers to jade that has been bleached with acid to remove mineral inclusions to enhance the beauty of a piece of jade. When artificial colour is added in the process, a B+C-jade is thus produced.
C-Jade is dyed jade without polymer impregnation. Although it looks attractive at the beginning, its colour fades gradually overtime and they are easily subjected to wear and tear.
Gold
The purity of gold is defined by its fineness or by the karat, which is 1/24 part of pure gold by weight.
Pure gold is alloyed or combined with other metals to change its characteristics such as its colour and hardness and/or to reduce its cost.
24K gold is valuable because of its high gold content. It is popularly used to make jewellery because
of its malleability and its attractive rich gold colour. However, pure gold is soft and is less ductile
than the other gold alloys, such as the 22K or 18K gold. Thus although 22K and 18K gold do not
share the deep yellow colour that pure gold enjoys, they are often used to set diamond and
gemstone jewellery.
As gold will oxidise and turn dull overtime due to exposure to air, it is therefore a good practice to keep gold jewellery in a pouch or seal them in a bag to maintain its lustre.
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