The original menorah, as first detailed in Exodus 25:31-40, was formed from one piece of pure beaten gold weighing 3,000 shekels of silver (over 7 stones). It was said to symbolise the burning bush in which God appeared to Moses , and was used to light and decorate the temple in the days of Moses.
Modern Jews believe that it is sinful to replicate items from the temple, so modern menorahs are usually slightly different from how it is detailed in the Torah. It is now used in Jewish homes during Hannukah to remind Jewish families to be light in the world.
31 You shall make a lampstand of pure gold. The base and the shaft of the lampstand shall be made of hammered work; its cups, its calyxes, and its petals shall be of one piece with it; 32 and there shall be six branches going out of its sides, three branches of the lampstand out of one side of it and three branches of the lampstand out of the other side of it; 33 three cups shaped like almond blossoms, each with calyx and petals, on one branch, and three cups shaped like almond blossoms, each with calyx and petals, on the other branch—so for the six branches going out of the lampstand. 34 On the lampstand itself there shall be four cups shaped like almond blossoms, each with its calyxes and petals.35 There shall be a calyx of one piece with it under the first pair of branches, a calyx of one piece with it under the next pair of branches, and a calyx of one piece with it under the last pair of branches—so for the six branches that go out of the lampstand. 36 Their calyxes and their branches shall be of one piece with it, the whole of it one hammered piece of pure gold. 37 You shall make the seven lamps for it; and the lamps shall be set up so as to give light on the space in front of it. 38 Its snuffers and trays shall be of pure gold. 39 It, and all these utensils, shall be made from a talent of pure gold. 40 And see that you make them according to the pattern for them, which is being shown you on the mountain.