On top of this there is a large Iron Ore deposit in Buttala - Tambapani (orange soil) / Iron Oxide
http://online.wsj.com/article/SB10001424127887324077704578361491643425354.html?mod=googlenews_wsj
For BLUE fans they say the following:
"The country also produces gemstones including rubies and sapphires, which the government forecasts will contribute $1.2 billion to gross domestic product in 2013. "
@Sanju where are you.