Algae Becomes Art in the Board Game Diatoms

By Keith Law | May 22, 2025 | 10:30am

Photos courtesy of Ludoliminal Games

Tabletop Reviews board games

Algae Becomes Art in the Board Game Diatoms

Listen to this article

In Victorian England, a very curious art form flourished: making intricate patterns from the microalgae known as diatoms, single-celled organisms that range from five microns (or .005 millimeters) to 200 microns and that have colorful cell walls made of silica. That gives them a jewel-like appearance, and intrepid artists would use their varied shapes and colors to create detailed designs. These artworks were invisible to the naked eye, comparable to the proverbial angels dancing on the head of a pin, except for the whole not-existing part. (If you know about diatoms now, it’s probably because you bought their fossilized remains for your garden in the form of diatomaceous earth, which can help condition the soil and maybe kill a slug or two.)

Diatoms the board game draws on this now-extinct tradition, where players will collect diatoms in five shapes and five colors and try to create patterns on their personal boards to match the three base criteria and perhaps another criterion from a ‘guest’ judge, who may be chill or persnickety, depending on the challenge you want. It’s a satisfying game that works in a competitive aspect in how you gain those diatoms, although I found I wanted it to go just a little longer.

The game play in Diatoms couldn’t be simpler: On your turn, you play a hexagonal water tile to the center of the board, making sure all edges match where adjacent to hex tiles already on the table. You then look at any complete intersections you’ve created to see what diatoms you get, based on the colors of the six triangles that meet at the new vertex. (It’s easier to see than it is to explain, I promise.) The diatoms come in five shapes, and you get diatoms matching the color and the number of triangles touching that vertex. If you create an intersection surrounded entirely by one color, you’ll draw two diatoms whose sizes add up to six. In most turns, you’ll end up with two or three diatoms for your troubles, but it’s possible to gain just one (usually a star, the largest size) or to gain four or even more if you create two vertices with your tile placement.

Most Popular

Diatoms board game review

After you take your diatoms, the next player may begin their turn, and you have until the start of your next turn to place the diatoms on your board. The boards are two-layer with insets for the diatoms, each of which only fits two of the five shapes, so you’re limited in your placement options. Once you mount a diatom, it’s there for the rest of the game. You’ll try to create some symmetries, to get as many shapes as possible in each concentric ring, and to get at least three of each color to try to meet the three base scoring criteria. The guest judges award greater point bonuses, and if you use the harder (persnickety) side, they can also hit you with deductions. Meeting all of these criteria at once is nearly impossible, of course, and you have very little idea of what diatoms you’ll get even one round from now, let alone later in the game, so you have to try to lean into a couple of them and stay nimble if the diatoms don’t crumble your way.

The tile-placement part of Diatoms gives the game interaction it wouldn’t have otherwise; you want to get certain diatoms for yourself, but some tile placements can set up the next player to make a bigger move and complete two vertices so they gain four or five diatoms in one shot. What you do on your own diatom board is your own business, however, so it needs that competitive component to avoid becoming multiplayer solitaire.

The game also has a solo campaign mode where you try to match the patterns on the solo deck without placing any extra diatoms; each pattern card tells you how many trays you can use to discard extra diatoms you collect, but once those are full, you’re toast. The components are also great, including the inset boards, five plastic ‘Petri dishes’ to hold the diatoms, and very detailed images on the diatom tokens.

I played Diatoms at three players, and did several solo runs, and I think it all works and has high replay value because you will always feel like you could have done a little better. I did find the game ended really quickly in terms of turns—I was surprised at how soon the tiles started to run out, which is how the game ends, and at how few diatoms you have when the game is over. You’re not going to fill your board or even come close, which puts at least two of the base judges’ criteria in direct conflict, so plan accordingly.

Games can easily take under a half an hour, and I think you could play this with kids, maybe as young as eight, although I have only tried it with adults so far. It reminds me a little of Azul in the combination of interaction in how you gain tokens, but then an individual aspect to where you place those same tokens and how you score them, without the cutthroat feeling that Azul can get (especially at two players).

Keith Law is the author of The Inside Game and Smart Baseball and a senior baseball writer for The Athletic. You can find his personal blog the dish, covering games, literature, and more, at meadowparty.com/blog.