Fig. 4: X-ray powder diffraction pattern of crushed zircon powder before and after immersing in each solution.
From: Dissolution and precipitation behaviors of zircon under the atmospheric environment

Left panel shows the pattern before immersion, and after immersing in 0.1 M NaOH (aq), ultrapure water, and 0.1 HCl (aq). Right panel shows unclear peaks at 32.5° and 38° in the pattern after immersing in 0.1 M NaOH (aq).