Striated Mark
Definition
Also called scratch, abrasion or scrape mark. Tool slides laterally across the surface and leaves parallel striations from microscopic imperfections on the tool's edge. Example: a screwdriver pry against a door jamb.
- How it's made
- Tool edge slides laterally across a surface, leaving parallel grooves from microscopic imperfections.
- Also called
- Scratch, abrasion, or scrape mark.
- What it reveals
- The spatial pattern of grooves and ridges matches the tool's unique surface texture, enabling identification.
Common questions
What creates the parallel lines in a striated mark?+
When a tool slides sideways across a surface, the tool's edge, which has microscopic pits and bumps, leaves parallel grooves and ridges. These parallel patterns are the identifying signature of the tool.
How is a striated mark different from a compression mark?+
A striated mark is created by lateral sliding motion, producing parallel grooves. A compression mark (impression) is made by direct pressure without sliding. Striated marks show direction and tool texture; impressions show shape and force.
Can a striated mark be traced back to a specific tool?+
Yes. Because the grooves and ridges reflect the exact microscopic surface texture of the tool's edge, forensic examiners can match a mark to a specific tool using microscopy and comparison techniques.
Related terms
- Impressed Mark
- Also called indented or compression mark. Tool is pressed perpendicularly into the softer surface and reproduces the contour of the tool's working...
- AFTE Range of Conclusions
- Association of Firearm and Tool Mark Examiners standard scale: Identification, Inconclusive (A, B, C), Elimination, Unsuitable for examination. The same scale used...
- AFTE Theory of Identification
- The Association of Firearm and Tool Mark Examiners' standard (1992, revised 2011) for reporting tool-mark comparison conclusions as Identification, Inconclusive, or Elimination...
- Asperity
- A microscopic surface protrusion on a tool's cutting edge; each asperity produces a groove in the substrate when the tool slides, contributing...
- Black-Box Validation
- A study design where examiners are given unknown questioned-vs-known pairs and asked to match or exclude without feedback, allowing error rates to...
- Class Characteristic
- A feature shared by an entire group of objects (every shoe of one model has the same sole tread; every tire of...
- Class Characteristics
- Features deliberately or systematically imparted to a group of items by design or manufacture, such as the calibre of a bullet, the...
- Combination Mark
- Both impressed and striated features in the same mark, typical of pry-bar and chisel attacks where the tool first bites into the...
- False-Positive Rate
- The proportion of authentic media files that a detection tool incorrectly classifies as manipulated or synthetic. Deepfake detectors and ELA tools both...
- Individual Characteristic
- A characteristic unique to a specific typewriter unit arising from manufacturing variation or service wear; used to identify or eliminate a specific...
- Individual Characteristics
- Surface features on a fired bullet or cartridge case that arise from random or unique events (tool wear, corrosion, service damage) and...
- Mikrosil
- Brand-name silicone polymer casting compound (also Microsil, AccuTrans) used to lift a fine-detail negative of a tool mark from the scene without...
Explained in these topics
- Tool Marks: Fundamentals, Striations and ImpressionsA tool mark produced by a sliding-tool edge, resulting in parallel grooves and ridges whose spatial pattern reflects the tool's surface texture.
- Tool Marks: Meaning, Types and ExaminationAlso called scratch, abrasion or scrape mark. Tool slides laterally across the surface and leaves parallel striations from microscopic imperfections on the too...