Diamond Explosion 7s is a slot built around RubyPlay’s signature Diamond Explosion mechanic, which serves as the foundation for an entire game series. The core idea of this mechanic is symbol expansion and the transformation of standard wins into layered, multi-stage bonus scenarios.

The Diamond Explosion Mechanic

When the Diamond Explosion feature is activated, adjacent prize symbols merge into larger symbol clusters. These clusters follow a distinct payout logic:

• a single prize symbol pays x1 of the bet;
• a 2×2 block (4 merged symbols) pays x10 of the bet;
• large clusters of 6 or more symbols have no fixed payout and instead trigger an internal mini-feature with a random multiplier and a chance to win one of four jackpots.

This nested structure makes the bonus phase the true core of the game.

Slot Overview

Diamond Explosion 7s is a classic Vegas-style slot featuring diamonds, sevens, cherries, and fruit symbols. The game uses a 5-reel × 3-row layout with 50 fixed paylines.

• Volatility: medium to high
• Hit frequency: 48.24%
• Maximum win: x8000 bet

Even traditional symbols are rendered in a crystal-like style, visually reinforcing the diamond theme across the entire slot.

Free Spins Feature

The number of free spins depends on the number of scatter symbols:

• 3 scatters – 8 free spins
• 4 scatters – free spins with a x5 win multiplier
• 5 scatters – free spins with a x20 win multiplier

During each free spin, one randomly selected reel is fully stacked with Wild / Diamond symbols. Every new prize symbol becomes sticky, gradually forming expanded symbol clusters.

Additional scatters during free spins trigger re-triggers, awarding extra free spins.

Key Features

Random Wild Reel Free Spins

Each free spin includes a reel filled exclusively with wilds and diamonds, dramatically increasing symbol density.

Link It Up Explosion

When 6 or more diamonds form an adjacent cluster, a dedicated bonus scenario is triggered within that cluster. This feature is available in both the base game and free spins.

Jackpot Pick Deluxe

Any wild symbol may activate a jackpot pick feature, allowing the player to select a guaranteed jackpot with a potential multiplier.

The slot includes four fixed jackpots, displayed above the reels (starting from x10 bet). These jackpots are not part of paylines but act as an additional reward layer within the bonus mechanics.

Symbol Behavior and Accumulation

The game features two special symbols:

• the standard Diamond Explosion Wild;
• the Diamond prize symbol.

If wilds appear in insufficient quantity to trigger a bonus, they animate upward into a visual accumulator. RubyPlay does not disclose its exact function; it appears to be a behavioral feature designed to suggest progress and energize the base game.

Bonus Gameplay in Practice

During free spins, diamonds gradually merge into larger clusters. Clusters of 6+ symbols are resolved only after the entire free spins sequence ends, at which point their internal multipliers or jackpots are revealed.

In one observed session:

• mega-symbol wins included €30 and €20;
• total free spins payout reached €65 on a €1 bet.

What I think 

Diamond Explosion 7s is a solid evolution of the classic hold & spin concept, enhanced by expanding symbol clusters, nested bonus mechanics, four fixed jackpots, and polished, recognizable RubyPlay visuals.

While not revolutionary, it is a well-structured and commercially sound slot, with most of its excitement concentrated in the bonus phase and a dynamic base game that effectively builds anticipation.