Diamond tile (pattern)
This blackwork pattern is formed by columns of small diamonds joined by horizontal lines. It is very similar to the diagonal tile pattern, except that the adjoining lines are straight and the pattern is larger in scale. As its name suggests, it resembles tiles in a diamond pattern.
Further Reading

Method
Complete a diagonal stitch from bottom left to top right over two intersections.
Bring the needle up at the base of the stitch and count over six threads to the left to complete a long horizontal stitch.
Bring the needle up at the right end of this stitch and complete another diagonal stitch from top left to bottom right, again over two intersections.
Repeat the last three steps directly below to complete a column. The diagonal stitches should share holes so that they form a continuous zigzag.
Working back up the area, complete a mirror image. This time, also add two diagonal stitches at the opposite end of the long horizontal stitch so it has chevrons at both ends.
The diagonal stitches should join and mirror those of the previous row so that small diamond shapes are formed between the horizontal stitches.
Continue to work columns across the shape to complete the pattern.

Structure of stitch
Embroidery Techniques
Variant Stitches
Related Stitches
Identifying Diamond tile (pattern)
A black work stitch pattern consisting diamonds connected to each other by a single line stitch.
References
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Various Authors, The Royal School of Needlework Book of Embroidery (2018) , p.150
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Becky Hogg, RSN Essential Stitch Guides: Blackwork (2010) , p.58