Our diamond grading services include estimating a diamond's 4C - Color, Clarity, Cut & Carat Weight. Standard round brilliant cut diamonds in the D-to-Z color range. IGAC provides the best watch grading services or appraisal service in the United States. Our reports are based on brands like Rolex, Piaget etc. Need a Jewelry Appraisal services This article explains jewelry appraisal procedures and some insight into jewelry insurance requirements. Jewelry Appraisal Services is an independent diamond appraisal services of diamonds, watches, and gemstones, owned by experienced Gemologist Steven Silver.