Ever since I purchased the board game Splendor I have been thinking about enhancing it by replacing the poker chip jewels with something more life like. I searched Amazon and local craft stores for jewels and just couldn’t find any that matched the game correctly. Turns out I needed to adjust my thinking slightly to solve the conundrum.
Board Game Geek member CavemanLogic provided the spark. Instead of black jewels he used purple. Genius. The gems he purchased are by far the best I have found and they don’t cost much either. Here’s the full run down from his post.
He selected a beautiful set of gems from Oriental Trading Company which includes green emeralds, blue sapphires, red rubies, and (purple) black onyx. The Translucent Treasure Jewels by Oriental Trading are simply stunning! However, you'll only need to use 1/3 of the set. Each color comes in all three facet cuts, but he recommend using only one facet cut for each color. For instance, emerald cut for the emeralds and sapphire cut for the sapphires. Round cut works best for the rubies, while I chose emerald cut again for the onyx since it looked the closest match.
If you're thinking of upgrading your Splendor game for the five-player variant, like I did, you'll need nine of each gem. However, you'll likely only get seven or eight of each color in the facet cut you want, so consider ordering two sets or be prepared to use a spare gem of another cut if necessary. You can also find a similar set on Amazon: Deluxe Assorted Pirate Jewels.
For diamonds, you can check out the dollar store or Michael's craft store. Alternatively, you can purchase Diamond Confetti Table Scatter "3/4" on Amazon. Just keep in mind that Amazon sells them in a one-pound bag (~240 pieces), so you may end up with more than you need.
To add a touch of authenticity, he collected metal Spanish replica coins from the now-defunct DeadMenTellNoTales.com site. They had 2-escudo coins (~ the size of a US quarter), 4-escudo (~ US half dollar size), and 8-escudo (Pieces of Eight, ~US silver dollar size) coins, which came in a shiny gold, shiny silver, antique gold, or antique silver finish. For this purpose, he recommends using the 4-escudo shiny gold coins from your collection. While it's harder to come by all the different size and finish combinations nowadays, you can still purchase smaller coins fairly easily. Here's a link for coins that should work just fine: Metal Pirate Coins.
If you prefer a more budget-friendly option, plastic pirate coins are a nice alternative.
Source: CavemanLogic on Board Game Geek