Karatmeter
The Karatmeter is a scientific instrument which uses X-rays to give an exact reading of the purity of gold. Due to its very high precision and fast result, X-ray analysis has been adopted by international agencies in India as part of the certification process used to hallmark gold. It is an accurate, non-destructive means of testing the purity of gold and other related elements. X-Ray method of Gold analysis gives the purity of gold up to 10-12 microns and hence it gives the analysis of coating only. Using this technique, the precise percentage or  karat (of karat) in a solid piece of jewellery can be determined in 30 seconds. It also accurately determines the element composition of all types of gold, white gold, platinum, silver, palladium, rhodium and related alloys. Energy dispersive X-Ray fluorescence (ED-XRF) is a simple, accurate and economic analytical methods for the determination of the chemical composition of many types of materials. It is non-destructive and reliable, requires very little sample preparation and is suitable for solid, liquid and powdered samples. It can be used for a wide range of elements, from Chlorine (17) to Uranium (92), and  provides detection limits at the sub-ppm level. There are many models of Gold Purity Testing machines available - from portable (light weight) to industrial grade machines. Apart from X-ray spectrometer technique, other older traditional methods are using the TouchStone and Acid to test the gold purity. But TouchStone and Acid are destructive testing - a tiny sample of gold is cut and then tested. The sample is rubbed on TouchStone and a drop of acid is put on it and the goldsmith observes the residue using a magnifying lens. Based on experience, gold smith can determine purity of sample. Karatmeter