Book Of Diamonds Slot Review
Magenta and electric-blue streaks fan out from a bright flare near the top of the screen, cutting diagonally across a dark purple void behind a thin gold reel frame. Book Of Diamonds spends nearly all of its imagination on that light show and almost none on complexity, and it’s the better game for it.
One symbol does the work of several here, and a spin of fortune before the free spins even begin decides what the round will be worth. Fewer moving parts than this format usually ships with – that’s the argument this game makes, and it holds up.
Spinomenal built it on a 5×3 grid with 10 paylines and a 95.9% RTP, and later revisited the same idea in Book Of Diamonds Reloaded. It sits in the studio’s long book-of lineage alongside Book Of Rampage and Book Of Titans, but it does fewer things than any of them. Fewer things, done brightly, may be exactly the point.
The Neon Reels and the Paytable
It’s a classic 5×3 setup with 10 fixed lines. All symbols pay left to right from the leftmost reel, only the highest win on each line is paid, and wins are multiplied by the bet per line. Nothing exotic in the mechanics; the neon frame and the laser-streak backdrop are doing the visual work.
The symbol set is old-school fruit machine stock: diamonds, sevens, bells, BARs and a run of fruit. The red Diamond is the one worth watching, paying from two of a kind and scaling steeply from there. All values below are multiples of the total bet.
- Diamond (red) – 2 pays 100x, 3 pays 1,000x, 4 pays 10,000x, 5 pays 50,000x
- 7 (red) – 2 pays 50x, 3 pays 400x, 4 pays 4,000x, 5 pays 20,000x
- Bell / BAR – 2 pays 50x, 3 pays 300x, 4 pays 1,000x, 5 pays 7,500x
- Watermelon / Plum – 3 pays 50x, 4 pays 400x, 5 pays 1,500x
- Orange / Lemon / Cherry – 3 pays 50x, 4 pays 250x, 5 pays 1,000x
That ladder is steep at the top and flat at the bottom. The fruit tier needs three symbols to pay anything at all, and even a full line of cherries returns 1,000x the total bet.
It sounds generous until you notice the same five Diamond symbols pay 50 times more. Two-of-a-kind pays exist only on the top three tiers, which shapes the base game more than anything else.
The Diamond, the 7, the Bell and the BAR will return something from a pair, while the fruit never does. That asymmetry is the whole character of the base game.
The Book is both wild and scatter: it counts as any symbol on the lines, and it also pays scattered anywhere on the reels. Three or more Books award a scatter prize on top of any line wins, and three or more also open the free spins round.
It’s the only special symbol in the base game, and everything else on screen is straight fruit.
Scatter Pays and the Trigger
Scattered Books pay regardless of position, and the prizes are set multiples of the total bet. They’re paid in addition to any regular line winnings on the same spin, so a trigger spin can collect twice before the round even starts.
- 3 Books – 2x the total bet, plus 10 free spins
- 4 Books – 25x the total bet, plus 10 free spins
- 5 Books – 250x the total bet, plus 10 free spins
The bet per line carries over into the free spins round unchanged from the spin that triggered it. A BUY button also sits in the interface, buying direct entry into the free spins round instead of waiting on the scatters.
The Free Spins Wheel
Trigger the round and you don’t get a fixed expanding symbol handed to you. Instead, a wheel appears carrying every regular symbol except the Book itself, and one spin of it decides which symbol will expand for the whole round.
It’s a small piece of theatre that fits the game’s look, and it adds a layer of luck before the free spins even begin. The wheel can hand the round a Diamond or hand it a cherry, and the difference between those two outcomes is the difference between a memorable round and a quiet one.
Once the wheel has picked, 10 free spins run on the same reels. The round can retrigger: land the scatters again during free spins and an additional 10 spins are added to the counter.
The Expanding Symbol
During free spins, after each spin’s result is determined, the chosen symbol expands to cover its reel positions and forms new paylines in addition to the existing ones. There’s a built-in brake on it: the symbol only expands when doing so will actually produce a win, so dead expansions don’t waste the mechanic.
When it does expand, the symbol pays its full paytable rate across all active lines, and it doesn’t need to sit on consecutive reels to count. Expanded wins are calculated separately from the original spin result.
That separate calculation is where the money is. A single free spin can pay twice: once on the lines as they landed, and again on the expanded formation stacked on top. Pair that with the Diamond’s 50,000x top-of-ladder rate and the ceiling on a good round is steep.
Our Honest Verdict
Overall Rating: 7/10
Most of a session here is fruit landing on 10 lines while a laser show covers the quiet spells, and the wheel that decides the bonus round before it starts is the one thing that sets this apart from plainer book slots. Every trigger carries a small gamble before the reels even move, and that’s the reason somebody picks this game.
The expanding symbol is the strength. It only grows when growth actually pays, it doesn’t care where it sits, and a single spin can settle twice – when the wheel hands it a top-tier symbol, the arithmetic turns serious in a hurry.
The weakness is everything around it: between triggers there’s fruit and nothing else, and the glow can only do so much with that. This suits players who like the book format boiled down to one idea and don’t mind the wait; the modifiers, minigames and layers live in other games. And on the rounds where the wheel hands over a Diamond, all that quiet between triggers stops mattering.
Book Of Diamonds FAQs
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What is the RTP of Book Of Diamonds?
Book Of Diamonds runs at an RTP of 95.9%. -
How do you trigger free spins in Book Of Diamonds?
Land three or more Book symbols anywhere on the reels. Three Books pay 2x the total bet, four pay 25x and five pay 250x, and all of them award 10 free spins in addition to the scatter prize. -
What does the expanding symbol do in Book Of Diamonds?
Before the free spins round starts, a wheel spins to choose one symbol. During the round, that symbol expands after each result to form new paylines on top of the existing ones, but only when the expansion creates a win. It pays across all active lines without needing consecutive reels, and expanded wins count separately from the original result. -
Can free spins retrigger in Book Of Diamonds?
Yes. Landing three or more Book symbols during the free spins round awards an additional 10 free spins on top of whatever spins remain. -
How many paylines does Book Of Diamonds have?
Book Of Diamonds has 10 fixed paylines, all paying left to right from the leftmost reel, with only the highest win on each line paid. -
What is the grid size of Book Of Diamonds?
Book Of Diamonds plays on a 5×3 grid: five reels and three rows. -
Can you buy the bonus on Book Of Diamonds?
Yes. A BUY button sits in the game’s interface, letting you purchase direct entry into the free spins round rather than waiting for three or more Book symbols to land. -
Who makes Book Of Diamonds?
Book Of Diamonds is made by Spinomenal, part of the studio’s long-running book-of series. Book Of Diamonds’ release date is 25 June 2020.
