Size, scale, weight and value.

July 4th 2015

Often the starting point for a custom piece of jewellery is an existing design. Today we will look at what happens when you modify a setting for a 3.5mm gem to suit a 12mm gem.

The pendant on the right in the photo below is from the shop section of this website and features a 3.5mm square cut Ceylon Pink sapphire and is made in 9ct white gold. I was asked by a customer to adapt it to a 12mm round cut gemstone and to make the pendant in 9ct yellow gold. A digital recreation of the design to those measurement is shown on the left. The pendants are shown in scale to each other.

This gemstone was found and cut by a relative of my customer and holds sentimental value to the family. The pendant is to be a gift to his wife.

After scaling the 2.4cm tall pendant to take a 12mm gemstone we now have a length of over 5cms. At 2.4cm the pendant was originally made without side gallery but with the extra length in the pendant and depth in the 12mm gemstone it was needed to add depth to the side of the design without too much more weight.

The original pendant weighed 2.2 grams. The new larger pendant made in 9ct yellow gold will weigh 11.5 grams. Doubling the length of the pendant has resulted in a 500% increase in the gold weight.

The 3.5mm square cut gem weighed 0.25 carats, the 12mm gem weighs 24 times that at over 6 carats.

Most of the time I am not asked to change the size of a design to this extent but it is a very good example of how gem and precious metal weights increase at a disproportionally higher rate than increases in length and width.

Hopefully you will now have a better understanding of why I am reluctant to give rough quotes and take the time to understand better how you want that new ring to look on your hand or new pendant around your neck.

Once I know the desired appearance I can calculate accurate sizes. This enables me to quote properly and to ensure that the piece I make for you looks exactly how you want it to.

One final point to remember is that this principle works inversely when you are trying to meet a budget.

Especially with the cost of diamonds, a small reduction in diameter can make a great difference to the weight and therefore the price. This may enable you to meet a budget whilst not impacting too greatly on the design.

All of these changes I can show you digitally during the design process.