Domain: commerce (Product Selection and Specification)
Problem: I am a jewelry maker planning to use the opal chips from this catalog to create birthstone jewelry for October 2025. The birthstone for October is opal. I specifically need opals with a blue tone that are not multicolored varieties (those without the "Multi-" prefix in their names). Among all the pure blue opals displayed in this catalog, what is the lowest price per gram based on the pricing of opal chips on October 1, 2025? Please express it in US dollars per gram.
Answer: $4.95 per gram