Making a macrame gemstone pendant is a rewarding handmade craft that employs ancient knotting techniques. It is most closely associated with the 1970s bohemian movement and the modern "boho chic" revival, rather than a specific historical era of mass production. 
How to Make a Macrame Gemstone Pendant
This guide describes how to create a simple net to hold an interchangeable or fixed gemstone using basic macrame knots.
Materials Needed
Step-by-Step Instructions
  1. Prepare the Base Loops: Take your two short cords and tie an overhand knot near the center of each, creating two small loops. Ensure the knots are at the same spot so they align evenly.
  2. Attach the Long Cords: Thread one long cord through both loops, evening out the tails, and tie a knot to form the base of your crystal net. Repeat with the second long cord, laying the pieces out to form a square or cross shape.
  3. Create the Net (Pouch):
    • Take one cord from one knot and one from an adjacent knot, and tie an overhand or a simple knot to join them.
    • Repeat this process for all neighboring pairs of cords, creating the first round of the net.
    • Continue this knotting process in subsequent rounds, working your way up the stone. Periodically check the fit by placing the gemstone inside to ensure the net fits snugly and the stone cannot fall through any gaps.
  4. Secure the Gemstone: Once the net reaches the top of the gemstone and holds it securely, tie an overhand knot with all the threads tightly and close to the stone. For a permanent fixture, add a small amount of glue before the final knot.
  5. Form the Necklace Strap:
    • Divide the cords above the gemstone into two sections.
    • Use square knots or a four-strand round braid to create the main necklace strap on both sides, ensuring they are equal in length. You can add beads here by threading them onto the central/core cords.
  6. Finish and Adjust: Plait or braid the remaining ends and tie a knot. For an adjustable closure, take a separate piece of cord and tie a series of square knots around the two parallel necklace ends. Trim the excess cords and carefully singe the ends with a lighter to seal them (for synthetic cords). 
Theme and Era
Macrame gemstone pendants are primarily a handmade item and are not specific to a single, formal historical "era" in the way that, for example, Victorian jewelry is.