Collection: Petrography Test Supplies

Beta Diamond Products is a specialist supplier of petrographic supplies for thin section preparation, polished section preparation, and archival storage for geological, mineralogical, and materials science analysis. Our petrographic slides are precision-made from Swiss glass at our USA facility and held to tight dimensional and optical tolerances. Every product in this collection meets the quality standards required for professional polarized light microscopy and reflected light ore microscopy.

Petrographic Slides — Technical Specifications

Petrographic slides differ fundamentally from standard laboratory microscope slides in their dimensional precision and optical quality. The critical specifications:

• Material: Colorless glass (Swiss-sourced)
• Dimensions — Standard format: 27 mm × 46 mm × 1.2 mm thickness
• Dimensions — Large format: 2 inches × 3 inches (50.8 mm × 76.2 mm) × 1.2 mm
• Surface quality: Ground and polished; freedom from striations, bubbles, and stress birefringence that would interfere with polarized light analysis
• Origin: Made in USA from Swiss glass

The dimensional precision of petrographic slides is not cosmetic — at the working magnifications of petrographic microscopy (40×–200×), any thickness variation introduces parallax errors and birefringence artifacts that can be mistaken for features of the rock or mineral specimen. Standard laboratory microscope slides should never be used as a substitute for petrographic slides in polarized light analysis.

Cover Glass — Technical Specifications

Beta Diamond cover glass is manufactured from colorless borosilicate glass to No. 1.5 specification (0.16–0.19 mm nominal thickness). No. 1.5 is the standard for petrographic analysis because it is the thickness for which high-numerical-aperture petrographic objectives (40×, 63×, 100×) are designed and corrected. Using thinner (No. 1) or thicker (No. 2) cover glass introduces spherical aberration that degrades optical resolution and compromises interference color accuracy under crossed polarizers.

• Glass type: Colorless borosilicate
• Thickness specification: No. 1.5 (0.16–0.19 mm)
• Flatness: Precision-cut and cleaned; flat to within 5μm over the cover glass area
• Available sizes: Multiple sizes to complement Beta Diamond petrographic slide formats

Slide Storage Boxes — Specifications

• Capacity: 25 slides per box (27×46mm format)
• Material: High-impact polymer
• Design: Individual numbered slots with friction retention; labeling surface on exterior
• Compatibility: Fits 27×46mm petrographic slides

What You Need for Complete Thin Section Preparation

For complete petrographic thin section preparation, you will also need: a diamond wafering blade (sintered, 0.014–0.020" thick) for initial rock slab sectioning, SiC grinding papers (120 → 240 → 400 → 600 grit) for lap grinding to 30 microns, and mounting epoxy with refractive index ~1.540 (Canada balsam or synthetic epoxy). For polished sections (ore microscopy, EPMA), add diamond suspension (9μm → 3μm → 1μm) for the polishing stages.

Frequently Asked Questions

What is the standard size and thickness of a petrographic thin section slide?

The internationally accepted standard petrographic thin section slide is 27 mm × 46 mm in the European/ISO format, or 2 inches × 3 inches in the American format. Slide thickness is 1.0–1.2 mm. The section itself is ground to a standard thickness of 30 micrometers (0.030 mm) — the thickness at which most rock-forming silicate minerals display their characteristic interference colors under crossed polarized light.

What is the difference between a petrographic slide and a standard microscope slide?

Petrographic slides are ground to a thickness tolerance of ±0.05 mm and are optically homogeneous — free of striations, bubbles, and stress birefringence that would interfere with polarized light analysis. Standard laboratory microscope slides have thickness tolerances of ±0.1 mm or more and are not tested for optical homogeneity. Using a standard slide in a petrographic microscope introduces birefringence artifacts and cannot be substituted for petrographic slides in quantitative polarized light work.

What cover glass thickness should I use for petrographic analysis?

Use No. 1.5 borosilicate cover glass (0.16–0.19 mm thickness) for all petrographic thin section analysis. No. 1.5 is the standard because high-numerical-aperture petrographic objectives (40×, 63×) are optically corrected for this thickness. Using thinner (No. 1) or thicker (No. 2) cover glass introduces spherical aberration that reduces resolution and distorts interference colors at high magnification.

How many slides do Beta Diamond slide boxes hold?

Beta Diamond slide storage boxes hold 25 petrographic slides (27×46mm format) in individual numbered slots. The boxes are made in the USA from high-impact polymer and are designed for archival storage. Larger format 2"×3" slide boxes are also available — contact us for specifications and pricing.