Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: 1/2 Carat TW Blue and White Diamond Ring in 10K White Gold
Product description: A beautiful blue and white diamond ring set in 10K white gold and featuring an all natural, blue diamond center stone weighing .23 carats. The side white diamonds weigh .23 carats and are prong set on this lovely white gold setting. A great everyday wear ring featuring all natural diamonds and top of the line workmanship.
Product feature: 30 Day Money Back Guarantee, 60 Day Complimentary Repair Service, Complimentary Packaging, ASIN: B005NHI6XI, Date first listed on Amazon: September 16, 2011, Average Customer Review: 5.0 out of 5 stars 1 customer review
Product brand: Szul
Target attributes: Silhouette
Answer: attribute: silhouette
value: None
source: None