<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
What types of gems are the most expensive?
<|assistant|>
The most expensive gems are usually rare, natural colored diamonds, gem-quality pink, blue, yellow and red star rubies, sapphires, and emeralds. Also extremely expensive are specimens of rare minerals like Topaz, Azurite, and Tourmaline.