In 1992, the value of natural gemstones, fresh water pearls, salt water pearls, coral and synthetic and simulant gemstones from the United States was $69.4 million, according to preliminary estimates by the US Bureau of Mines. The value of natural gem material produced was $51.2 million, a 53% decrease compared to 1991. The value of synthetic and simulant production was $18.2 million, a 5% decrease from the previous year. US production accounted for about 2% of the $3.1 billion of estimated US consumption of gems and gemstones. Total 1992 US imports of gem materials were $4.84 billion, according to the Bureau of the Census. Diamonds accounted for $4.14 billion, or about 86% of the total imports. Even in light of the US recession, the flow of gems and gemstones increased into the United States. US exports and re-exports of gem materials amounted to $1.61 billion. Of that, the significant portion was diamonds. Imports in 1992 increased slightly compared to 1991, while exports plus re-exports decreased 5% for the same period. Diamond sales by De Beers Centenary AG was $3.4 billion in 1992, a decrease of 13% compared to 1991 sales of $3.9 billion. Sales during the second half of 1992 were only $1.63 billion, 12% less than the $1.84 billion sales for the second half of 1991. A De Beers official said that the reduction in sales was the result of the economic conditions in the United States and Japan. De Beers controls about 80% of the rough, uncut diamonds sold in the world. Preliminary estimates of 1992 official world gem diamond production were 10.4 t (52 million carats), according to the Bureau of Mines, an 8% increase from 1991. Official production is the production reported by the governments of the producing countries or the mining companies and does not include the production marketed through unofficial channels. Production through unofficial channels historically has been estimated to be between 5% and 10% of official production, or an additional 520 kg to 1 t (2.6 to 5.2 million carats). During 1992, the percentage of unofficial goods may have been higher than the historical percentages because of problems in Angola and Zaire. Australia maintained its position as the largest diamond producing country. Production from Argyle increased to a record high of 7.8 t (39 million carats). Production from Argyle is 55% industrial and 45% gem and near-gem. Diamond production in other producing countries fluctuated, increasing in some, decreasing in others and remaining essentially unchanged in a few. Supplies of colored gemstones were strong because of increased production from a number of new deposits and from some old producing areas. Supplies of certain select gemstones were in tight supply. Therefore, prices increasedhigh quality rubies would be one example. African production of amethyst, aquamarine, emerald, gamet, ruby, sapphire, topaz and tourmaline increased in quantity and quality. Gemstone production also increased in Afghanistan, Brazil, Madagascar, Pakistan and Sri Lanka. There was a continued strong demand for synthetic and simulant gem stones. Both the quantity and value of imports and exports increased in 1992. Increased use of synthetics and simulants in solid 10 and 14 karat gold settings assure a growing market for these gems. The materials are being used to duplicate expensive originals as well as to create inexpensive originals. Complete lines of jewelry made with gold and synthetic or simulant gems are being manufactured for a wide range of consumer tastes. Cubic zirconia (CZ) is becoming a major force in the jewelry industry. It is estimated that US annual sales of CZ jewelry are now in the range of $400 million. Also, 1992 was the first year that a significant amount of Russian synthetic gemstones made their way into the United States and world markets.