Thai baht of weight for precious metals and gemstones. One baht = 15.244 grams. Since the standard purity of Thai gold is 96.5 percent, the actual gold content of one baht by weight is 15.244 × 0.965 = 14.71046 grams; equivalent to about 0.473 troy ounces. 15.244 grams is used for bullion; in the case of jewellery, one baht should be more than 15.16 grams. The Bank of Thailand adopted a series of exchange controls on 19 December 2006, which resulted in a significant divergence between offshore and onshore exchange rates, with spreads of up to 10 percent between the two markets.
Heavy metals is improved with the addition of thorium. Tellurium is added to copper and steel alloys to improve their machinability; and to lead to make it harder and more acid-resistant. The biocidal effects of some heavy metals have been known since antiquity. Platinum, osmium, copper, ruthenium, and other heavy metals, including arsenic, are used in anti-cancer treatments, or have shown potential. Antimony (anti-protozoal), bismuth (anti-ulcer), gold (anti-arthritic), and iron (anti-malarial) are also important in medicine. Copper, zinc, silver, gold, or mercury are used in antiseptic formulations; small amounts of some heavy metals are used to control algal growth in, for example,