A rare and significant American emerald known as the Carolina Queen is valued at $350,000-450,000 ahead of a December 10 auction at Bonhams Los Angeles.
Found in the Appalachian Mountains, near the town of Hiddenite, North Carolina in 1998, the stone is the largest and finest example of a North American emerald ever discovered.
It weighs approximately 18.8 carats.
The region has been described as one the most geologically complex in the world, yielding significant quantities of gem quality emeralds, rubies and sapphires along with a rare variation of kunzite referred to as hiddenite in honour of the place of its discovery.
The Carolina Queen was discovered in the 1990s by miner James K Hill and was one of two gems cut from the rough.
The smaller emerald is known as the Carolina Prince and sold privately for a reported $500,000 in 1999.
Dancing on a Rainbow, a two-colour agate cameo and multi-gem-set gold clock made by Manfred Wild, carries an estimate of $160,000-200,000.
The piece features a fine black and white cameo of a woman holding a rainbow comprised of multi-coloured gemstones, with a handmade clock by F Jutzi.
The clock is fitted with a tourbillon action and gold plated wheels, along with a Breuget spiral counterbalanced hour wheel, set with a variety of precious stones.
Two large conch pearls are valued at $140,000-180,000.
The pair, believed to be the largest conch pearls ever found, were discovered in the Caribbean and feature superb lustre and flame-pattern iridescence.
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