Pyrex bowls, measuring cups and other thick Pyrex containers won't take direct heat and will break. You need thinner Pyrex, such as a drip coffee pot or a beaker. Even these, however, can break if you put them directly on a hot plate. No matter what you use, I would put the dissolving vessel inside of a larger vessel that won't break and put the larger vessel on the hot plate. An ideal larger vessel is a Corning Ware dish.
Since you have such a small amount of gold (about 2 grams), the size of the dissolving vessel is important. If it's too large (wide), the small amount of acids I've recommended won't cover the ring. Ideally, you should should use a beaker not larger than 250 ml. I would also cover the beaker with a watch glass or a small heatproof ceramic saucer while heating, to prevent the acid from evaporating.
Thinking further, you may be able to get away with using a very small Pyrex dish inside of a Corning Ware dish. Heat it very slow to start with and you may not break it. If it does break, you will still catch everything inside of the Corning Ware dish.
The nitric leach method I've given will only work on karat golds of 10K, or less. If above 10K, the larger amount of gold will block the penetration of the acid. The alloying metals in karat golds are usually copper, silver, nickel, and zinc, all of which will dissolve in nitric acid.
If the silver is over 10%, which it very well may be, you will not be able to dissolve all the alloy directly in aqua regia. The simplest way is to try nitric alone first.
The standard method on this forum is to melt enough silver with the karat gold to reduce the gold content to 25%. This is called inquartation. The base metals and silver are then dissolved in nitric acid, as in the method I gave you on my first post. Actually, my method of using nitric to treat 10K or less gold is identical to the inquartation method, except you don't have to go through the trouble of melting, adding silver, and shotting the alloy.
If the gold content is much more than the 9K marking (which is very unlikely) and my method doesn't work, you haven't lost anything. You can still use the inquartation method.
The method I gave for aqua regia avoids the need for urea or boiling down. The most important thing, however, is to use only enough nitric in the aqua regia to barely dissolve the gold. If you end up adding too much, you'll have to get rid of it by using Harold's standard method of boiling down.
