If you have ever seen chocolate that looks like it has dust embedded in it, it is called a bloom and it means that the chocolate maker did something wrong. It can be that they got water in the chocolate (bad juju) or that the over-heated the chocolate and didn't cool it properly. This process is called Tempering. Not to get too much in the weeds, but there are 6 different types of crystals. The beta crystals melt above 94 degrees and they are the ones you want to see because they have the snap and the shine you want.
You can melt the chocolate, pour it out on a marble slab and stir and spread it out to slow the cooling so that the beta crystals form. I have tried too many times and ended up re-melting the chocolate. A tempering machine is stupid simple, but at $200 and up, well, I am cheap.
Using this method, you will get good looking chocolate without bloom
Step 1: This Is a Little Tricky...
...but it is doable. There are a couple of guidelines to keep in mind. If the weather is damp (I am in Seattle, so it is always damp) you are going to need to be more careful. When humidity hits chocolate, it blooms and that is not good looking or tasting. If you get more water into the chocolate, it will seize and that is not good either. You will know it when you see it (above).
Step 2: Moving On
1. Measure out your chocolate and divide it into thirds.
2. Chop it up. The smaller the pieces the faster will melt.
3. Set up your double boiler. Keep in mind that the boiler part of that is in name only. You want the water in the bottom half at a bare simmer. If you have the real deal, great, but if not a small pot and a metal or glass bowl will do. Make sure that the water doesn't touch the bottom of the bowl and the the pot doesn't have a pouring spout. The spout makes a wonderful channel for the steam to burn your hand and seize your chocolate.
4. Take 2 thirds of the chocolate and put it in the double boiler (real or improvised) and melt it. You will want to leave it alone until it starts to sag and then stir it with a metal or plastic (no wood) spatula.
5 Once it melts, take it off the heat and put the liner/bowl on a towel and dry it and let it sit for a minute or so, stirring gently. If you have a thermometer (electric or laser is best) try to keep the temp above 100 degrees. If it drops below that, put it back onto the heat and repeat.
6 Add the rest of the chocolate and stir gently until it melts. There will be enough heat to melt the last third.
Step 3: Enjoy!
Now you can use this for dipping strawberries (make sure they are dry first and keep drying them as you dip, because water on the surface will make blooms in later dips), making bark (pour it out on a baking sheet lined with parchment and swirl in other things like melted caramel, melted marshmallows, melted peanut butter and nuts or dried fruit or bacon) and break it up when solidified. Anything you want.