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: 14kt Gold Lab Alexandrite and Diamond 8x4mm Marquise Antique Style Ring
Product description: This antique style ring features a 8X4mm marquise-cut center stone, surrounded by 14 sparkling diamonds. For a more antique look, this is a perfect choice for an engagement ring. The marquise cut {gemstone} makes for quite a classic look, and the 14 diamonds surrounding it will make your loved ones eyes sparkle with glee. The cut out pieces of gold around the stones, create a unique and beautiful stylish design. This ring will be a true testament to the infinite love you two share.
Product feature: Premium quality, color-changing, lab-created Alexandrite (chyrsoberyl), 14 karat solid gold, Made in the USA, Shipping Information: View shipping rates and policies, ASIN: B07CK11GY6, Date first listed on Amazon: September 7, 2014, Average Customer Review: 2.5 out of 5 stars 2 customer reviews
Product price: $399.00
Product brand: Jewels For Me
Target attributes: Silhouette
Answer: attribute: silhouette
value: engagement
source: product description