Explains why BIS Hallmark certification confirms gold purity but not nickel content, and why that distinction matters for children specifically — thinner, more permeable skin, longer continuous wear, and cumulative sensitisation that can cause a reaction to a previously "safe" piece. Covers alloy composition by karat (18K ~75% gold vs 14K ~41.7% alloy), what causes nickel ions to leach onto skin, and practical steps: asking a jeweller to confirm nickel-free alloy in writing, checking clasps and small hardware, and favoring higher-karat gold. References American Academy of Dermatology guidance on nickel as a leading contact allergen. See our https://6a61dd0714a9e.site123.me/blog/choosing-jewellery-for-a-child-with-a-nickel-allergy-what-to-verify-beyond-hallmark for nickel-conscious design options in our earrings collection, and https://ladybugjewels.in/ for our made-to-order alloy confirmation process. Every piece is made-to-order in Mumbai in BIS Hallmark certified 14K or 18K gold.