Great quilting projects are like great wilderness explorations. Cut here, turn a corner here, try a new path, and eureka! You’re in a completely different place than you started.

Agate Quilt | Purl Soho

This Agate Quilt is a real Lewis-and-Clark adventure, an exploration of a rich mineral palette and of a vast and unknown sewing technique: Y seams. It turns out that, unlike mapping the American west, Y seams are barely life threatening at all!

Agate Quilt | Purl Soho

The reward at the end of this journey is both a beautiful quilt inspired by earthy geological colors and a map to a whole new world of Y-seam quilting! .-Molly

Agate Quilt | Purl Soho

Materials

Agate Quilt | Purl Soho

Our Agate Quilt Bundle includes…

You will also need…

Size

Finished dimensions: 50 by 62 inches

Notes

Prewash and dry all fabrics (but not the batting).

Use a precise ¼-inch seam allowance for all piecing. Use your machine’s ¼-inch foot, if you have one.

Pattern

Cut

Most of the work of this quilt is in the cutting! Take it slow and mark every piece as soon as it’s cut. Keep the pieces organized by their Fabric letter.

There are two kinds of cut pieces in this quilt: Diamonds and Strip Pieces.

Diamonds

Cut all the Diamonds on the bias as 3 3/8-inch squares. The grain of the fabric will run from point to point.

From Fabric G: Cut six 3 3/8-inch squares, on the bias

From Fabric H: Cut seven 3 3/8-inch squares, on the bias

Agate Quilt | Purl Soho

Using the Chaco Pen on Fabric H and the Chalk on Fabric G, on each Diamond draw lines ¼ inch from and parallel to each edge, as shown above. Make sure that the points where these lines intersect are clear and especially mark two points across from one another. These two points are the Corner Intersections.

Strip Pieces

All of the Strip Pieces are 2 ½ inches wide, cut from selvage to selvage. If you have never cut selvage-to-selvage strips like this, you can learn how with our Rotary Cutting Tutorial.

Strip Pieces longer than 42 inches need to be pieced together. With right sides together, align one of the 2 ½-inch edges and sew together with a ¼-inch seam allowance.

Agate Quilt | Purl Soho

Most of the Strip Pieces start or end with a 45° angle. Measure the desired length of the Strip Piece and cut the 45° angle at that point, as shown above.

Agate Quilt | Purl Soho

For pieced Strip Pieces and fabrics that have a clear right and wrong side, you will cut the 45° angle so that it is oriented at the top right or left corner, or at the bottom right or left corner, as shown above.

For these how-to photos, we use fabrics with a clear right and wrong side, but if you are using a fabric that doesn’t have a right and wrong side (as we did in the finished quilt), you only need to worry about the position of the 45° point on the Strip Pieces that have been pieced. Otherwise, just make sure to cut the 45° angle at one end, you can flip the piece later to change its orientation.

With the Chaco Pen, make a note on each Strip Piece that says its length and Strip number.

Cutting List

NOTE: This Cutting List is also available as a printable PDF.  Once you print it out, you can check off each piece after you have cut it.

From Fabric A:

  • For Strip 1: 40 ½ inches- with the 45° point at the top right corner 10 ½ inches- with the 45° point at the top left corner
  • For Strip 3: 6 ½ inches- with the 45° point at the top right corner 44 ½ inches- with the 45° point at the top left corner
  • For Strip 6: 46 ½ inches- with the 45° point at the top right corner 4 ½ inches- with the 45° point at the top left corner
  • For Strip 10: 50 inches- with straight ends

From Fabric B:

  • For Strip 2: 40 ½ inches- with the 45° point at the bottom right corner 10 ½ inches- with the 45° point at the bottom left corner
  • For Strip 7: 46 ½ inches- with the 45° point at the bottom right corner 4 ½ inches- with the 45° point at the bottom left corner
  • For Strip 12: 12 ½ inches- with the 45° point at the top right corner 38 ½ inches- with the 45° point at the top left corner
  • For Strip 15: 38 ½ inches- with the 45° point at the bottom right corner 12 ½ inches- with the 45° point at the bottom left corner

From Fabric C:

  • For Strip 4: 6 ½ inches- with the 45° point at the bottom right corner 44 ½ inches- with the 45° point at the bottom left corner
  • For Strip 11: 50 inches- with straight ends
  • For Strip 20: 6 ½ inches- with the 45° point at the bottom right corner 44 ½ inches- with the 45° point at the bottom left corner

From Fabric D:

  • For Strip 5: 50 inches- with straight ends
  • For Strip 8: 26 ½ inches- with the 45° point at the top right corner 24 ½ inches- with the 45° point at the top left corner
  • For Strip 13: 12 ½ inches- with the 45° point at the bottom right corner 38 ½ inches- with the 45° point at the bottom left corner
  • For Strip 16: 50 inches- with straight ends For Strip 18: 36 ½ inches- with the 45° point at the bottom right corner 14 ½ inches- with the 45° point at the bottom left corner
  • For Strip 23: 16 ½ inches- with the 45° point at the top right corner 30 ½ inches- with a 45° point at the top left corner AND a 45° point at the top right corner 5 ½ inches- with a 45° point at the top left corner
  • For Strip 28: 4 ½ inches- with the 45° point at the bottom right corner 46 ½ inches- with the 45° point at the bottom left corner

From Fabric E:

  • For Strip 14: 38 ½ inches- with the 45° point at the top right corner 12 ½ inches- with the 45° point at the top left corner
  • For Strip 17: 36 ½ inches- with the 45° point at the top right corner 14 ½ inches- with the 45° point at the top left corner
  • For Strip 19: 6 ½ inches- with the 45° point at the top right corner 44 ½ inches- with the 45° point at the top left corner
  • For Strip 21: 50 inches- with straight ends
  • For Strip 25: 28 ½ inches- with the 45° point at the top right corner 22 ½ inches- with the 45° point at the top left corner
  • For Strip 27: 4 ½ inches- with the 45° point at the top right corner 46 ½ inches- with the 45° point at the top left corner
  • For Strip 30: 8 ½ inches- with the 45° point at the bottom right corner 42 ½ inches- with the 45° point at the bottom left corner

From Fabric F:

  • For Strip 9: 26 ½ inches- with the 45° point at the bottom right corner 24 ½ inches- with the 45° point at the bottom left corner
  • For Strip 22: 50 inches- with straight ends
  • For Strip 24: 16 ½ inches- with the 45° point at the bottom right corner 30 ½ inches- with a 45° point at the bottom left corner AND a 45° point at the bottom right corner 5 ½ inches- with a 45° point at the bottom left corner
  • For Strip 26: 28 ½ inches- with the 45° point at the bottom right corner 22 ½ inches- with the 45° point at the bottom left corner
  • For Strip 29: 8 ½ inches- with the 45° point at the top right corner 42 ½ inches- with the 45° point at the top left corner
  • For Strip 31: 50 inches- with straight ends

Piece the Quilt Top

Agate Quilt | Purl Soho

 

NOTES: If you click on the diagram above, you can download and print it, enabling you to cross off each Strip number (along the right edge of the diagram) after you have pieced it and added it to the quilt top.

HOW TO PIECE THE STRIPS WITH A DIAMOND (Y SEAMS)

When there is a Diamond set into two Strips, you first piece together the two Strips and the Diamond, and then piece the pair of Strips to the quilt top. These paired Strips are represented on the diagram by a little bracket next to the two Strip numbers. For instance, Strips 1 and 2 are a pair. All of the paired Strips involve a Y-shaped join where a Diamond and two Strip Pieces meet. This is called a Y Seam.

To demonstrate a Y seam let’s piece together Strips 1 (represented by the gray fabric) and 2 (represented by the orange fabric) with a G Diamond.

Gather the pieces you have cut for Strips 1 and 2, as well as a Fabric G Diamond. From both Fabric A and B you have a 40 ½-inch Strip Piece and a 10 ½-inch Strip Piece.

Agate Quilt | Purl Soho

With right sides together, pin the 40 ½-inch Fabric A Strip Piece to the 40 ½-inch Fabric B Strip Piece along the shorter of their long horizontal sides. Using the Chaco Pen, mark a line ¼ inch from and parallel to the 45° cut, as shown above.

Sew these two pieces together along the pinned edge, stopping and backstitching when you reach the marked line. This is the Left Group for Strips 1 and 2.

With right sides together, pin, mark, and sew the 10 ½-inch Strip Pieces of Fabric A and B in the same manner. This is the Right Group for the Strips 1 and 2. Put this Group aside for now.

Agate Quilt | Purl Soho

Orient the Left Group so that Fabric A is facing up, the seam is on top, and the 45° angle is to the right. Pick up the 45° point of the Fabric A Strip Piece and open it to the left. Finger press this fold so that the Fabric A piece forms a mirror image of the exposed Fabric B piece. Notice that the bottom raw edges are flush and that the resulting shape is a triangle (with one squared off tip).

Agate Quilt | Purl Soho

With its wrong side facing up and one of its Corner Intersections on top, place the Diamond on top of this triangle, aligning the sides. Stick the tip of a pin into the Corner Intersection of the Diamond and then stick the pin into the exact point where the seam on the Fabric A and B pieces stops. Place the pin here.

Agate Quilt | Purl Soho

Pin the right hand side of the Diamond to the diagonal edge of Fabric B.

Lower your needle directly into the first pinned point, at the Corner Intersection of the Diamond piece. Take a couple forward stitches, then a couple of backstitches, making sure to never sew past the Corner Intersection. Sew down the pinned side along the marked line, all the way to the end of the Diamond. You don’t need to backstitch at the end of the seam.

Agate Quilt | Purl Soho

Remove the Left Group from the machine and orient it so that now the Fabric A 45° point is at the left and the Strip Pieces are to the right. Pin the Diamond edge to the diagonal edge of Fabric A.

Agate Quilt | Purl Soho

Sew the pinned side down in the same manner as before, making sure to backstitch at the Corner Intersection and to not sew beyond it.

Unfold the pieces and press the seam allowances of the Diamond flat towards the Strip Pieces and the seam allowance of the two Strip Pieces towards the darker fabric.

When you unfold and turn these pieces right side up, they should come together neatly at the Diamond’s corner. The point where the three pieces meet is a Y Seam!

Agate Quilt | Purl Soho

Now repeat this process with the Right Group, only this time when Fabric A is facing up and the seam is on top, the 45° point will face to the left. Pick up the 45° point of the Fabric A Strip Piece and open it to the right.

Agate Quilt | Purl Soho

With right sides together, place the unsewn corner of the Diamond on top of the Right Group’s exposed triangle, lining up their sides. Stick the tip of a pin into the Corner Intersection of the Diamond and then stick the pin into the exact point where the seam on the Fabric A and B pieces stops. Place the pin.

Now pin the Diamond to the diagonal edge of Fabric B.

Starting at the Corner Intersection, sew down the pinned side, backstitching at the beginning of the seam. This time Sew all the way to the end of the Diamond, past the next marked intersection. You don’t need to backstitch at the end of this seam.

Agate Quilt | Purl Soho

Remove the piece from the machine and orient it so that now the Right Group Strips Pieces are to the left. Pin the final side of the Diamond to the diagonal edge of Fabric A.

Agate Quilt | Purl Soho

Sew the pinned side down in the same manner, starting by backstitching at the Corner Intersection and then sewing along the entire side of the Diamond.

Press the seam allowances of the Diamond flat and the seams of Fabric A and B towards the darker side.

The Strip 1 and 2 pair is now done. You will piece all of the paired strips together in the same manner, first sewing together the Left Group, then the Right Group, then sewing the Diamond to the Left Group, and finally to the Right Group. (The paired Strips 23 and 24 are slightly different in that you make three Groups. You’ll find more info on that below.)

For piecing the entire quilt top I found it most helpful to just follow the diagram, checking off the pieces as I went, but below is the order of piecing written out, in case you find that easier to follow…

– Piece together Strips 1 and 2 with a G Diamond.

– Piece together Strips 3 and 4 with a G Diamond.

– Sew the top edge of Strip 3 to the bottom edge of Strip 2.

– Sew the top edge of Strip 5 to bottom edge of Strip 4.

– Piece together Strips 6 and 7 with an H Diamond.

– Sew the top edge of Strip 6 to the bottom edge of Strip 5.

– Piece together Strips 8 and 9 with an H Diamond.

– Sew the top edge of Strip 8 to the bottom edge of Strip 7.

– Sew the top edge of Strip 10 to the bottom edge of Strip 9.

– Sew the top edge of Strip 11 to the bottom edge of Strip 10.

– Piece together Strips 12 and 13 with a G Diamond.

– Sew the top edge of Strip 12 to the bottom edge of Strip 11.

– Piece together Strips 14 and 15 with a G Diamond.

– Sew the top edge of Strip 14 to the bottom edge of Strip 13.

– Sew the top edge of Strip 16 to the bottom edge of Strip 15.

– Piece together Strips 17 and 18 with an H Diamond.

– Sew the top edge of Strip 17 to the bottom edge of Strip 16.

– Piece together Strips 19 and 20 with an H Diamond.

– Sew the top edge of Strip 19 to the bottom edge of Strip 18.

– Sew the top edge of Strip 21 to the bottom edge of Strip 20.

– Sew the top edge of Strip 22 to the bottom edge of Strip 21.

– Piece together Strips 23 and 24 with a G and an H Diamond. To do this, create three groups of sewn-together Strip Piece: a Left Group, a Middle Group, and a Right Group. First sew the G Diamond to the Left and Middle Group, then sew the H Diamond to the Middle and Right Groups.

– Piece together Strips 25 and 26 with a G Diamond.

– Sew the top edge of Strip 25 to the bottom edge of Strip 24.

– Piece together Strips 27 and 28 with an H Diamond.

– Sew the top edge of Strip 27 to the bottom edge of Strip 26.

– Piece together Strips 29 and 30 with an H Diamond.

– Sew the top edge of Strip 29 to the bottom edge of Strip 28.

– Sew the top edge of Strip 31 to the bottom edge of Strip 30.

Note:

After you sew the Strips together, always press the seam allowances so that the seam allowances of the Diamonds lie flat. (If the seam doesn’t contain any Diamonds, just press it towards the darker side.) If you have two Diamond pieces along the same seam that go in different directions, you can turn the seam allowance once you reach the second Diamond to allow both Diamond allowances to lie flat.

You’re all done with the top!

FINISH THE QUILT

Agate Quilt | Purl Soho

For instructions on how to make a quilt sandwich and attach the binding please refer to Corinne’s Denim Pinwheel Quilt and scroll down to the Finishing the Pieced Top section. I quilted my top by stitching in the ditch along all the seams, following the horizontal seams up and over the points of the Diamonds, but you can quilt yours in any style you like!