Hallmarking is the accurate determination and official recording of the proportionate contents of precious metal in jewellery. Hallmarks are thus official marks used in many countries as a guarantee of purity or fineness of gold jewellery.
Your two main priorities when storing your gold and silver are to avoid tarnishing/dulling and avoid scratching. To avoid tarnishing you will need to reduce the amount of moisture in the air. Store each piece of jewellery in a separate cotton or jewellery bag. The bag needs to be able to breathe, if the bag is air tight it may sweat which will cause tarnish. Good quality jewellery bags are usually treated with chemicals that reduce tarnish. A good quality jewellery bag will save you a lot of trouble in the long run. The pieces should be stored individually, if stored together the pieces will scratch each other. If available place a moisture absorbing product inside your jewellery box. White chalk, charcoal or silica gel will absorb the moisture which causes tarnish.
Softer gemstones scratch easily, other types of gemstones crack and certain gemstones can also be damaged changes in heat. Store your gemstones in individual bags and keep them in an area with relatively stable temperatures. Certain porous gemstones like Emerald should not become too dry or they may in fact crack. For this reason these gemstones should be re-oiled every year or so depending upon your climate.
Gold jewellery prices are dependent upon the purity of the gold used or karat weight, the market value of gold and the level of craftsmanship and design of each jewellery piece.
24 karat = 99.9 % gold
22 karat = 91.7 % gold
20 karat = 83.3 % gold
18 karat = 75.0 % gold
16 karat = 66.7 % gold
14 karat = 58.3 % gold
12 karat = 50.0 % gold
10 karat = 41.7 % gold