Understanding Pennsylvania Bluestone Grades & Sorting

First: What Does “Grade” Mean in Natural Stone?

Unlike manufactured pavers, natural stone varies from piece to piece. In bluestone, “grade” typically refers to a combination of:

• Color consistency (blue/blue-gray vs. mixed full-color)
• Surface character (natural markings, iron tones, darker mineral areas)
• Squareness and sizing (how consistent the pieces are in shape and dimensions)
• Thickness range (how uniform the stone is for installation)
• Edge finish / processing (natural edge, snapped edge, sawcut, thermal, etc.)

Important: grade is not the same as strength. Many “seconds” or “full-color” stones are just as durable as select stone—they’re simply less uniform in appearance.

Common Bluestone Color Grades

“Select” Blue / Blue-Gray

Often the most requested look: cool, consistent tones with a more uniform appearance. Great for projects where a clean, predictable color is desired.

Full-Color (Natural Blend)

A natural mix of blues, grays, browns, and occasional darker areas. Many customers love the character and warmth—especially for sidewalks, paths, and rustic patios. Full-color is often a strong value choice.

“Seconds” (Appearance-Based Sorting)

“Seconds” typically means the stone falls outside narrow appearance standards—often due to more noticeable color variation, iron staining, or darker inclusions. This can be a great option when you want a unique look at a better price.

Common Bluestone Sizing & Shape Categories

Pattern Cut (Rectangular Sizes)

Pattern bluestone is cut into standardized rectangular sizes (for example, 12x12, 12x18, 18x24, etc.). It installs efficiently and creates a cleaner, more geometric look.

Thermal / Sawn Cut (Uniform + Clean Edges)

Often used for modern designs and formal patios. These pieces typically have more consistent thickness and crisp edges (depending on the product).

Irregular (Natural Shapes)

Irregular bluestone is made of natural polygonal shapes. It’s popular for informal patios, garden paths, and landscape designs. It requires more fitting and “puzzle work,” but the finished look is very natural.

Steppers / Large Slabs

Used for garden paths, landscape walkways, and stepping stone layouts. These are often selected for visual impact and ease of placement.

Thickness Sorting (Why It Matters)

Thickness is one of the biggest factors in how bluestone performs in different applications. Bluestone is commonly sorted into thickness ranges, such as:

• 1"–1.5" (often used for patios and walkways on a properly prepared base)
• 1.5"–2" (great for heavier traffic, commercial patios, and more robust installations)
• 2"–3"+ (ideal for steps, landings, coping, and areas needing extra mass and stability)

In general: the more consistent the thickness, the faster and easier the install. A wider thickness range can still work well—especially for experienced installers—but it may require more leveling.

Edge Sorting: Natural vs. Snapped vs. Sawn

• Natural edge – rustic, organic look; great for informal patios and walls.
• Snapped edge – a more controlled “split” edge; still natural but more consistent.
• Sawn edge – clean, straight lines; often chosen for modern or formal layouts.

Many projects look best with a mix: for example, sawn edges for tight joints and a clean pattern, or a snapped edge for a traditional bluestone feel.

How to Choose the Right Grade for Your Project

Sidewalks & Walkways

• Best value: Full-color / seconds (great character, hides wear)
• Thickness: 1.5"–2" is a strong choice for long-term durability
• Tip: Mix tones evenly—dry-lay first for balance

Patios & Outdoor Living Spaces

• Classic look: Select blue/blue-gray pattern for a clean, consistent appearance
• Rustic look: Full-color irregular for a natural “old world” style
• Tip: Choose texture (natural cleft vs thermal) based on traction and style

Steps, Landings & Caps

• Go thicker: 2"–3"+ for stability and longevity
• Consider: sawn edges for a crisp stair look, or snapped for traditional

Walls & Landscape Features

• Look for: pieces with mass and consistent bedding surfaces
• Full-color often looks fantastic in rustic retaining walls and garden borders

What to Ask When Ordering Bluestone

A few simple questions help ensure you get exactly what you’re imagining:

• Is this select blue or full-color?
• What is the thickness range?
• Are the edges natural, snapped, or sawn?
• Is it pattern cut or irregular?
• What base and installation method do you recommend for this product?