All the Treasures of the World: Gems is devoted to "the gleaming apple of every adventurer's eye" -- gems. Written by Joel Sparks, this 12-page PDF sells for $2 from Faster Monkey Games and is a collection of rules for determining the value, type, size, and quality of 100 different types of gems. The PDF is written specifically for use with Labyrinth Lord, but I doubt that there'd be much difficulty in adapting to most old school fantasy RPGs.
Gems consists of six parts of varying length, each one providing some further complexity to the subject of precious stones. Each section is modular, so a referee need not use them all if he doesn't wish to do so, but, taken together, they do make gems potentially much more interesting than they often are in most campaigns. The first section provides a new random gem values table that replaces the one in Labyrinth Lord, mostly by providing for the option of gems worth less than 10 gp. The second section is a collection of gem types by value, so that a referee can randomly determine exactly what type of stone the 100 gp gem he just rolled up actually is. These tables alone make the PDF worthwhile, adding some much-needed color to the rather bland gem tables in the LL rulebook.
The third section provides tables for determining the size and quality of gems. Thus, you can generate a "larger, flawed" gem or a "smaller, flawless" one. Size and quality are naturally additional factors for determining a gem's value. The fourth section provides three pages of gem descriptions, each entry stating not only what a gem looks like in terms of color but also whether it's transparent and the typical cuts and sizes in which it comes. This is another excellent section that aids a great deal of color (no pun intended) to otherwise bland gem tables in the LL rulebook. Section four also includes notes on several of the gem types, along with discussions of unusual phenomena, such as chatoyancy and asterism.
The fifth section presents a system for evaluating gems that's simple and easy to use, based on a character's Intelligence score, modified according to his background and professions, if any. These rules include options for dealing with uncut stones, as well as fakes and misidentified gems. The sixth section treats the process of buying and selling gems, jewelry, and other valuables, so it's applicable to a wide variety of circumstances in which adventurers might find themselves. Again, the rules in this section are simple and straightforward. They add complexity, certainly, but not so much that they'd significantly slow down play. And they can easily be ignored in situations where the added detail serves no purpose.
All in all, All the Treasures of the World: Gems is a well-written and useful PDF expansion to Labyrinth Lord. It's truly what I'd call "supplementary" and I mean that positively. One can profitably play Labyrinth Lord without this product, but its additional information and rules bring something useful and, I think, fun to the table, at least for those who care about the differences between a tourmaline and a turquoise. It's definitely not a "must have" product, but it's nevertheless a very good one and one I'll be using in my own campaign.
Presentation: 7 out of 10
Creativity: 8 out of 10
Utility: 6 out of 10
Buy This If: You want to add some depth and complexity to gems as treasure in your fantasy roleplaying games.
Don't Buy This If: You don't have much interest in gems beyond their gold piece value.