<prompt> Black scab is formed at4-5 days6-7 daysLess than 24 hoursAfter 7-10 days  <response>: Age of abrasion Less than 24 hours bright red - reddish scab 2-3 days reddish- brown scab 4-5 days dark brown scab 6-7 days black scab ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 114 