Yesterday before her rock collecting trip, she had 48 - 6 = <<48-6=42>>42 mineral samples.

She has 1/2 the number of gemstones, so she has 42 / 2 = <<42/2=21>>21 gemstone samples.

# Answer

21
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Joan collects rocks. In her collection of rock samples, she had half as many gemstones as minerals yesterday. Today, she went on a rock collecting trip and found 6 more mineral samples. If she has 48 minerals now, how many gemstone samples does she have?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
21
Joan collects rocks. In her collection of rock samples, she had half as many gemstones as minerals yesterday. Today, she went on a rock collecting trip and found 6 more mineral samples. If she has 48 minerals now, how many gemstone samples does she have?
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