Appearance is a comprehensive descriptor of a substance's visual characteristics, encompassing multiple physical properties including physical state, color, transparency, texture, and form. In the context of a Safety Data Sheet (SDS), appearance provides a holistic description that helps in the identification and characterization of substances.
The appearance of a substance is influenced by several factors:
The appearance of a substance is significant in an SDS for several reasons:
Appearance in SDSs is typically described using a combination of standardized terms:
| Category | Common Descriptors |
|---|---|
| Physical State | Solid, liquid, gas, semi-solid |
| Color | Colorless, white, black, red, blue, green, yellow, etc. |
| Transparency | Clear, transparent, translucent, opaque, cloudy, hazy |
| Solid Forms | Powder, crystalline, granular, flakes, pellets, beads, fibrous, monolithic |
| Liquid Characteristics | Viscous, non-viscous, solution, suspension, emulsion, oily |
| Surface Properties | Shiny, dull, matte, metallic, lustrous, waxy |
| Texture | Smooth, rough, coarse, fine, sticky, dry |
Solids with a regular, repeating arrangement of atoms or molecules, often with flat faces and straight edges.
Examples: Table salt, sugar, many pharmaceutical compounds
Solids without a crystalline structure, often with irregular shapes and surfaces.
Examples: Glass, many polymers, waxes
Finely divided solid particles, which can vary in fineness from coarse to ultrafine.
Examples: Flour, talc, many metal oxides
Solid particles larger than powders, often with a defined size range.
Examples: Sugar granules, fertilizer pellets, catalyst beads
Transparent liquids that allow light to pass through with minimal scattering.
Examples: Water, many alcohols, acetone
Translucent liquids that scatter light, often due to suspended particles or emulsions.
Examples: Milk, some cleaning solutions, certain suspensions
Liquids with high resistance to flow, often thick and slow-moving.
Examples: Honey, glycerin, motor oil
Semi-solid materials with properties between solids and liquids, often jelly-like.
Examples: Hair gel, silica gel, hydrogels
Changes in appearance can be important safety indicators:
Users should be alert to unexpected changes in appearance, as these may indicate potential hazards or quality issues.
According to GHS and various regional regulations (EU CLP, US OSHA HazCom, etc.), the appearance of a substance should be indicated in Section 9 of the Safety Data Sheet as part of the description of basic physical and chemical properties. While specific appearance descriptors may vary, a comprehensive description typically includes physical state and color at minimum, with additional characteristics as appropriate.
When describing appearance in an SDS: