Diamond

is the hardest gem and the purest form of carbon. It ought water—hence to be as pure and colourle as a drop of the purest “ first water." Diamonds are sold by weight, 1 carat stones costing from £10 to.£30. 5 carat stones from £200 to £300, 10 carat stones from,£800 to £1000. The Mattam diamond is 367 carats, the Orloff 194$ carats, the Regent 136!, the Koh-i-no or 106, and the Braganza 1880. If the latter, which is the- Portuguese crown jewel, is really a diamond, it is worth £5,000,000. The Koh-i-no or, which is one of the British crown jewels, belonged to the Emperor Aurenzebe, and was reduced by his unskilful or dishonest workmen from 793 to 186 carats. It was captured by the British troops in the Sikh War, and presented to the Queen. It had to be re-cut, which further lowered its weight. It is valued at £140,000. The Regent or Pitt diamond cost the Duke of Orleans £135,000, and is valued now at £450,000. Catherine II. of Ru ia paid for the Orloff diamond about £90,000 in cash, an annuity of £1000, and a title of nobility. The methods of testing stones are ciuite simple. Diamonds are so hard that they cannot be scratched by anything except another diamond they are not electrified by heat and they cannot be; seen through, c.g. so as to distinguish; the marks of the skin on a hand in which they may be lying.