Dragonvale: How do I breed a Topaz Dragon?

While agent86 has been dutifully hogging the limelight, I've been in the background obsessing over progress oriented games such as DragonVale. Games such as this fascinate me. At the face of it, you have a one dimensional farming game. Breed. Wait. Hatch. Repeat. However, I often find a way to look in between the cracks and crannies of the game's objectives to find additional challenges. What is the mathematically ideal way to breed a given dragon species? What are the statistical odds of the Dragon Race? What is the ideal population of habitats in your park, and what dragons should be placed in each? Stay tuned, as I seek to answer all of those questions, and more (and by all means pose your own in comments).

In the mean time, there is a particularly burning question at hand. It is after all a new month, and a new Limited Gemstone Dragon is afoot. As you may know, Gemstone dragons require a unique, non-obvious breeding pair. On the day these dragons drop I tend to find that the Dragonvale Wiki does a rather poor job of providing timely information. Instead I seek out sources like Macenstein, who seems to often be quick to find the winning pair. In this case, the pair has thankfully already been found the details are:

November Gemstone Dragon - Topaz

Breeding Pair: Firefly Dragon + Cactus Dragon

Breeding Time: 30 hours or 24 hours with upgrade

Availability: Month of November

Type: Gemstone

Price: 1500 Gems (like you'd really pay that)