First Gemstones: Beryls
When pale colored or colorless, beryls are also inexpensive and fairly easy to find. (This excludes the more celebrated, colorful, and expensive varieties, such as aquamarine, emerald, morganite, and red beryl).
Either quartz or beryl would make a good place to start learning.
More Options for Beginners
Garnets and tourmalines also make fine first gemstones. However, these usually cost more than quartz or beryl. Thus, most instructors don’t recommend them to novices. Nevertheless, I feel it’s important to cut something worthwhile, even if you’re learning. After all, you’ll spend many hours faceting a stone. Your garnets and tourmalines will be worth something when you’re done cutting.
Natural or Synthetic?
I prefer my students start practicing on a natural stone. However, if you really want to cut synthetics, laser glass makes a good starting point. Avoid cubic zirconia (CZ) and lab-created corundum and spinel. These are much harder to cut and polish, especially for beginners. In addition, these synthetic gems require more laps and additional time.
What Size Rough Should I Cut?
I recommend you start with a moderate-size rough stone, from 5 to 20 cts (1 to 4 grams). This gives you room to make mistakes and correct them. (You’ll most likely need it).
What Type of Gemstone Should I Cut Second?
If you started with quartz or beryl, try a garnet next. After that, try a tourmaline.
When you’ve cut at least one stone each of quartz, beryl, garnet, and tourmaline and feel more confident, move on to topaz. Light colored or blue topaz is inexpensive. Due to its perfect cleavage, you’ll find topaz a bit more difficult to work with. It also takes more effort to polish.