Location
The Kew Sapphire Deposit is located on the rural property of “Kew” in the upper reaches of Kings Plains Creek, within the Kingsland Sapphire Field, New England Gemfields. The property of Kew is located 45 km north-east of Inverell, and approximately 36 km north-west of Glen Innes.
Geological setting
The Kew Valley Sapphire Deposit is one of a number of sapphire deposits that make-up the New England Gemfields in north-eastern NSW.
Sapphire classification
The sapphires from Kew have been classified into 5 separate size categories ranging from stones greater than 2.9mm in diameter to those greater than 7.5mm in diameter, and an additional category for stones heavier than 5 carats. Nearly 3/4th of the production is madeup of stones smaller than 5.5mm in size, which is highly sort after by Asian gemstone traders for the calibrated cut stone market.
Grade categorization
Run-of-mine sapphire rough from the Kew Valley Sapphire Mine is classified into five different grades depending on the color, transparency and quality of the stone. This standard grading system is preferred by Asian rough stone buyers and has been used on the New England Gemfields for decades.
Sapphire
Sapphire Chemistry and Properties xiii
- Sapphire is a variation of the mineral corundum, an aluminum oxide (Al2O3).Sapphire stones are one of the hardest natural gemstones in the world,approaching 9 out of the possible 10 on the Mohs scale. Diamond is the only natural gemstone which is harder than sapphire. Sapphire has a vitreous-toadamantine luster. Its refractive index is in the range of 1.66-1.67.
- Sapphire has pleochroic properties i.e. it displays a lighter and more intense color when viewed at different angles. It has a melting point greater than 2,000 degree Celsius and is infusible and insoluble.
Sapphire Uses
- Jewelry: Sapphire is extensively used in all forms of jewelry, with the blue colored sapphire being the most widely used. Nevertheless, recently, yellow, pink and orange colored sapphires have also become very popular.xiv
- Industrial Applications and construction: Sapphire is used in infrared optical components, small windows, wristwatches and in some insulation applications, being one of the hardest natural gemstones.xv Due to its properties, it is also used in the construction industry.
- Electronic: Sapphire offers superior mechanical properties, chemical stability and light transmission,making it ideal for some applications in electronics. Gallium nitride on sapphire is commonly used in blue light-emitting diodes (LEDs).
Sapphire Sources and Production
- Sapphire comes in two varieties — natural and synthetic. Natural sapphire is obtained only through mining,but synthetic sapphire is grown through a procedure called Verneuil process, which was first developed by French chemist Auguste Verneuil in 1902.xvi
- Currently, Sri Lanka and Madagascar are the most important sources of sapphire in the world.Commercial deposits of sapphire are also present in Thailand, Laos, India, Australia, Nigeria, the US,Slovakia, Borneo, Russia, Romania, Burma and in some South American countries.
- The sapphire deposits in South Madagascar are considered as the greatest find since the discovery of sapphire in Sri Lanka and Burma, due to their quality and size. Estimates suggest that Madagascar supplies 50% of all sapphires in the world market, most of which are dug and processed by hand artisan miners.xvii
Sapphire Market Driver
- The color of sapphire drives the demand for jewelry purposes.xviii This is furthered by the increased consumer spending for jewelry.
- In electronic applications, Nitride LEDs have been the main driver for sapphire market for several years and this market is expected to grow at a CAGR of 15% till 2012. Almost all (88%) of sapphire demand for LEDs comes from the Asian market with Taiwan alone accounting for 58% of sales and Japan accounting for 19%. xix
- In 2010, strong growth in the LED market resulted in a sharp increase in the demand for Sapphire substrates used for the manufacturing of blue and white GaN based LEDs. Demand for finished substrates jumped from 1MM two inch equivalent (TIE) in December 2009 to close to 2MM TIE in December 2010.xx
- To meet the growing demand for sapphire substrates, seven top global suppliers of sapphire ingots are expected to almost double their capacities in 2011, creating a huge opportunity for the sapphire mining industry.
Sapphire Price Trend
- For jewelry uses, the price of sapphire depends on various factors including its origin,color,weight,clarity, cut and treatment.The price change because of these factors is exponential. For example, a 1ct Ceylon blue sapphire may cost around $1200 but a slight decrease in color and clarity can bring down the price to about $800. xxi
- The supply of sapphire substrate in 2010 was insufficient to meet the increased demand from LED manufacturers.This led to a significant increase in the prices of sapphire materials during that year. During the last quarter of 2010, the average selling price for substrates increased by about 30%. The prices of 2-inch wafers have risen much more rapidly than other wafer sizes.xxii
- Going forward, we expect that the increasing capacities of the world’s major suppliers of sapphire substrate will solve the supply shortage problem and will push the price towards its long-term average.
