Instead of asking someone else... why do you look it up on the internet?? This was the answer that I got.
What is the smallest mountain in the world?
Mount Wycheproof in the Mallee region of Victoria, Australia is the smallest mountain in the world. It stands 47m above the surrounding plain. The town of Wycheproof is built on it's 'slopes'. It was mistakenly classified as a mountain by the Surveyor-General even though by size, it should be a hill. (See http://maps.google.com.au/maps?ll=-36.074499,143.23394&z=16&t=h&hl=en)
Mount Wycheproof is predominantly granite and has a quarry on the east face of the mountain. It is also where Whycheproofite was discovered. (See http://webmineral.com/data/Wycheproofite.shtml)