The Sultanate produced minerals worth over OMR 142.24 million during the year 2014, according to data on mineral production published in the Statistical Year Book 2015. Over the three years of 2012-2014, the total value of minerals produced in the Sultanate showed a continued decline with corresponding figures being 159.75 million, 146.64 million and 142.24 million rials. During 2014, Oman exported its entire production of 2300 ton of copper cathodes earning revenues of OMR 6.15 million. Also, 165 kg of gold and 3285kg of silver valued respectively at over OMR 2.52 million and OMR 732,000 were sold by the Oman Mining Company in the same year, the report says. During the period, production of marbles rose to 1.56 million tons valued at OMR 21.76 million as against 1.25 million ton worth OMR 18.04 million produced in year 2013. Oman produced 8.72 million ton limestone worth OMR 9.9 million in 2014, with corresponding figures for 2013 being 5.48 million ton valued at OMR 7.87 million. As much as 3.38 million ton of gypsum worth OMR 5.09 million, and 751,200 ton of chromite valued at OMR 22.85 million were also produced in 2014. Laterite production reached 753,100 ton valued at OMR 2.25 million, while quartz production touched 282,900 ton valued at OMR 1.13 million. During the period Oman produced 72,100 ton copper worth over OMR 22.58 million and 37500 ton manganese worth OMR 417800, while kaolin production exceeded 66,600 ton valued OMR 199,800. Other minerals produced in 2014 include 12,900 ton salt (OMR 451,000), 305,400 ton mud (OMR 1.66 million) and 60,200 ton sand dune (OMR 150,500).