Gemsmith comes in two varieties: Ruby and Diamond. Both games feature similar gems and hexagonal play fields, and yet the gameplay for each is unique thus offering two very different experiences.
Ruby will seem familiar to anyone who has played Sudoku. The object of the game is to place the colored gems within the cells of the hexagonal play field such that no two gems of the same color appear within the same continuous row. Each hexagonal cell can be part of three (3) different rows, so the challenge is in placing the gems in the correct places as each level has only one solution. You may swap the current gem with one already placed on the board, and there is no time limit imposed.
Analysis: Ruby differs from Sudoku in that the player is not free to choose what symbol to place next on the board. I see this choice of interface as both a strength and a weakness to the game. It is a strength since a player may quickly pick-up and get started with the game simply by clicking on a free cell and placing a gem. The weakness being this same interface may result in a no-win situation and therefore force the player to reset the board and start over.
I like the idea of a hexagonal Sudoku game, and playing with colored gems has proven to be quite popular with the casual games audience. If you like Sudoku, be sure to check out Tonypa's Ruby game.
Diamond will be familiar to anyone who has played games like Net. The object of the game is to rotate the gems such that connectors form a continuous circuit throughout the play field thus turning all gems from brown to yellow. Each level is randomly generated and there is only one solution that leaves no connector unused.
Simply click on a gem to rotate it clockwise, or press Shift while clicking to rotate counter-clockwise.
A bit easier to play than Ruby, and with levels that increase in size as the game progresses, Diamond is a wonderful game for anyone with even a minor case of OCD.
Note: Since I am unable to link to his games directly, I have not provided my usual "Click" links that open the respective game in a pop-up window. Tonypa's games had previously been looted and appear illegally all over the Web. As a countermeasure to the piracy, he has added scripts to his site that require you to enter 'through the front door' each time you play. Here's the front door: Click.