PA Bluestone Flagstone Colors: Blue, Gray, Green, Brown, Lilac, Rust

Lilac Irregular PA Bluestone Flagstone Color

Lilac Irregular PA Bluestone Flagstone Color

Pennsylvania Bluestone, also known as flagstone, comes in a variety of shapes and textures as discussed in an earlier article entitled PA Bluestone Flagstone – Shape & Texture.  All of these options also come in multiple colors.

When most people think of flagstone they think blue:  Pennsylvania Bluestone.  However, most flagstone is actually not blue in color.

The color of flagstone is caused by the minerals in the ground where the flagstone is formed.  Most flagstone is full color also called variegated.  This mean that a full range of minerals run through the quarry such that each piece from that quarry can be blue, gray, green, brown, lilac, or rust in color.  Most pieces will exhibit multiple colors swirled together in unpredictable patterns.  Many believe it is the unique combinations of color that gives flagstone its most compelling beauty.  Natural clef pattern and natural clef irregular flagstone have the most color variety and drama.  In full color thermal flagstone, much of the drama is removed by the flaming process.  Multiple colors still exist but appear more subtle.  And the rust color is nearly non-existent in thermal.  Tumbling also reduces the dramatic lines of color separation, although not quite as much as the thermal process.

“True Blue” Pennsylvania bluestone occurs less often in nature than full color. True blue flagstone comes out of the quarry in a consistently blue-gray color.  A range of blue shades can appear in true bluestone, but the variation is very minor.  A large blue flagstone patio may exhibit what appears as waves of blue shades similar to looking at water, but the variation will be negligible.  Blue flagstone appears the same color in all forms, i.e., natural clef, thermal, and tumbled.

Occasionally, a large section of a bluestone quarry will be deep reddish – purple.  The industry calls this color lilac.  Lilac flagstone may also have rust color veins but the underlying color is lilac rather than blue.

When choosing color for your Pennsylvania Bluestone project, be sure to see samples.  Samples will give you an idea of the range of variety and the core colors of the various options.  However, remember, flagstone is a natural stone.  Variety is inherent in the product and in the attraction of natural stone.  The material you purchase and its installation will be unique.  If you are looking for color consistency, you should consider a manufactured, simulated flagstone product.

2 thoughts on “PA Bluestone Flagstone Colors: Blue, Gray, Green, Brown, Lilac, Rust

  1. Carmen K Partridge

    I seek a hearth of real green (grey green) bluestone 3″ x 65″ x 50″, ideally natural cleft. I have seen sa Les on f this predominantly green bluestone before, but am having trouble sourcing it in this size. Is it a color that comes from PA quarries, or generally from elsewhere? If it is typically native to another region, would you kindly tell me where.
    Thank you!

    1. woodward Post author

      Carmen, I left a voice mail to help but: bluestone comes both “blue” and “variegated” (sometimes called full color or off color). Some suppliers only carry blue or only carry variegated. To get the green color (as well as browns and reds). So, when shopping for a hearthstone predominantly green, you need to ask your local dealers if they carry variegated or full color.


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