The Mosaic #13 Quilt Block Free Tutorial

Hello, quilt enthusiasts! Today, we’re diving into the charming world of the Mosaic #13 quilt block. This delightful block, which is part of the historic series originally introduced by the Ladies Art Company, features a captivating pinwheel and star design at its heart—reminiscent of those playful pinwheel toys from childhood. Whether you choose modern or traditional fabrics, the Mosaic #13 block is sure to add a dash of whimsy and elegance to your quilting projects. So, gather your materials, and let’s start stitching this beautiful pattern together!

Fabric Requirements for a 12″ Finished Mosaic #13 Quilt Block:

Light/White: 6 – 4″ squares
Medium/Purple: 4 – 4″ squares
Medium/Blue: 2 – 4″ squares
Dark/Burgundy: 4 – 4″ squares

Sewing Directions:

Half Square Triangles:

Step 1:

Using two White 4″ squares and two Burgundy 4″ squares, make Half Square Triangle units as shown. Here are the steps corresponding to the images in the picture below by going from left to right, top to bottom.

Match up a White square and a Burgundy square right sides together. Mark a diagonal line from corner to corner on the back of the White square and sew 1/4″ (or a little less) on each side of the line.
Cut along the diagonal line. You will have 2 half-square triangle patches.
Open up the patch and press the seam allowance toward the Burgundy fabric.
Square up/trim the units to 3.5″ square.

Step 2:

Repeat for a total of four White/Burgundy Half Square Triangle units.

You can find a detailed tutorial for sewing Half Square Triangles (HST) at https://quiltembroiderypdf.com/how-to-sew-a-basic-half-square-triangle-block

Step 3:

Repeat Steps 1 and 2 only substituting the Medium/Blue for the Burgundy fabric. Press the seam allowances toward the White fabric.

Step 4:

Repeat Steps 1 and 2 only substituting the Medium/Purple for the Burgundy fabric. Press the seam allowances toward the Purple fabric.

Step 5:

Repeat Steps 1 and 2 only substituting the Medium/Purple for the White fabric. Press the seam allowances toward the Burgundy fabric.

Putting It All Together:

Step 6:

Lay out all the Half Square Triangle units as shown in the picture below.

Step 7:

Sew the units into four rows as shown below.

Step 8:

Press the seam allowance in opposite directions from row to row. You can see in the picture below that I’ve pressed rows 1 and 3 toward the left and rows 2 and 4 are pressed toward the right.

Step 9:

Sew the four rows together.

Step 10:

Press the seam allowances whichever direction you wish. I’ve pressed the middle one using the tweak/twirl/furl method and the outer two are pressed toward the center. You’re finished!

Layout Ideas:

Here’s your basic 4 x 4 layout with similar colors to the tutorial:

This is the same layout but with a 1.5″ sashing and cornerstones added.

This monochromatic example has a different Mosaic block used as an alternating block for a lovely design.

A simple chain block is used as the alternating block in this version.

This is an on-point layout in warm colors with plain background setting triangles.

In this on-point layout another simple chain block was used for the alternating block and for the setting triangles.