Can I make this with only two colors instead of four?

Yes, the round count stays the same either way. Just repeat your two colors across the six rounds. The mandala look comes from the rounds, not a fixed color rule.

How do I keep the center from puckering?

Pull the magic circle closed firmly after round 1. A loose center gap will show once you add later rounds. Check it lies flat before moving on.

What hook size works best for a firm coaster?

The pattern calls for a 3.5 mm hook with DK yarn. That combination keeps stitches tight enough to hold a mug well. Sizing up will make a looser, softer coaster.

Mandala coaster crochet pattern for a calm evening

About This Pattern

This mandala coaster is a small round thing for a busy table. It works up in six rounds, from a magic circle out. I like it for a coffee break, not a whole evening. It needs DK yarn in four colors, a 3.5 mm hook, and a little patience for the joins. One coaster is quick. A set of four is a proper project.

In the basket

DK yarn (lightweight yarn number 3, or light worsted weight) in four colors: one main color and three contrasting colors
3.5 mm crochet hook
Yarn needle (for weaving in ends)
Scissors

Abbreviations

ch: chain
sl st: slip stitch
sc: single crochet
dc: double crochet

Mandala coaster crochet pattern for a calm evening

Main Pattern

Round 1Begin with a magic circle (or ch 4 and join with a sl st to form a ring). Ch 3 (counts as first dc).Work 11 more dc into the ring (a total of 12 dc counting the initial ch-3).Pull the end of the magic circle to tighten and close the center gap.Sl st to the top of the ch-3 to join.
Round 2Ch 1 and cut yarn. Switch to second color. Join new color with a sl st to any dc.Ch 3 (counts as first dc), dc in the same stitch.Work 2 dc in each dc around, join with a sl st to the top of the ch-3.

You should have 24 dc at the end of this round.

Ch 1 and cut yarn.

Round 3Join third color with a sl st in any space between the sets of 2 dc from the previous round.Ch 1, then work 3 sc in the same space.Skip the next 2 dc, work 3 sc between the next set of 2 dc around.Join with a sl st to the first sc.Ch 1 and cut yarn.
Round 4Using the main color, join with a sl st to any sc from the previous round. Ch 1, then work 3 sc, one in each of the next 3 sc.Perform a long sc by finding the space between the dc's two rounds below (you're going into Round 2 here, creating an "interlocking" effect), pull up the loop to the height of the other sc's and complete the sc.Continue 3 sc across, 1 long sc down into the previous color's round around.Join with a sl st to the top of the first sc.Ch 1 and cut yarn.
Round 5Join fourth color with a sl st to the top of any sc. Ch 1, sc in the same stitch.Ch 1, skip the long sc and next sc, sc in the next sc repeat around.After the last repeat, ch 1, then join with a sl st to the first sc.Ch 1 and cut yarn.
Round 6 (Final)Using the main color, join with a sl st to any ch-1 space.Ch 1, work 3 sc in the same ch-1 space.Work 3 sc in each ch-1 space around.Join with a sl st to the first sc.Ch 1 and cut the yarn, weave in all ends.

More pictures

Mandala coaster crochet pattern for a calm evening — photo 2

Mandala coaster crochet pattern for a calm evening — photo 3

Mandala coaster crochet pattern for a calm evening — photo 4

Mandala coaster crochet pattern for a calm evening — photo 5

Mandala coaster crochet pattern for a calm evening — photo 6

Before the first stitch

Check your gauge with a small swatch. A tight center keeps the coaster flat.
Read round two once through. It asks you to cut yarn and rejoin with a slip stitch.

Minutes per piece

Round 1 - magic circle base about 10 minutes because it is just 12 double crochets and a join
Rounds 2 to 6 - color changes and shaping about 45 minutes because each round adds a new color and more stitches to place evenly

Other yarns that work

cotton, DK weight Gives crisper stitch definition and a flatter coaster. Cotton is stiffer, so blocking helps it lie even.
acrylic, worsted weight Makes the coaster slightly larger and softer. Move up to a 4 mm hook to match the thicker yarn.

Where it ends up

Set one under a mug on a wood table, to catch condensation without a coaster.
Stack four in a basket, for a housewarming gift that fits on any shelf.
Use one under a small potted plant, paired with a plain saucer.

Small notes

Pull the magic circle tight before round two. A loose center will show through the whole coaster.
Cut yarn cleanly at each color change. Neat ends save time weaving in later.
Keep your ch-3 the same height every round. Uneven chains make the mandala sit crooked.
This pattern uses US crochet terminology, and is worked in the round starting with a magic circle.

Little questions

Can I make this with only two colors instead of four?
Yes, the round count stays the same either way. Just repeat your two colors across the six rounds. The mandala look comes from the rounds, not a fixed color rule.
How do I keep the center from puckering?
Pull the magic circle closed firmly after round 1. A loose center gap will show once you add later rounds. Check it lies flat before moving on.
What hook size works best for a firm coaster?
The pattern calls for a 3.5 mm hook with DK yarn. That combination keeps stitches tight enough to hold a mug well. Sizing up will make a looser, softer coaster.

Original pattern: https://crocheteverything.com/crochet-beautiful-mandala-coaster-pattern-for-home-decor/