The Crystals... probably my most favoured race, I simply love them
Economy and exploration is not so different... do what you can and stay hidden as long possible. Sometimes I don't colonize planets that are too far away to stay hidden... but only when I know that my opponent is already so close that I just want to have a surprise for him.
The ships... the shiplist is extremely useful.
I build, Opals, Rubies, Emeralds, Diamond Flames and Crystal Thunders
The opal is a good ship if you can't afford anything else. With mk4 torps you can kill freighters or stop them with a small web. I also love to fly around with just 10 mk4 torps and use "mdq" to drop just one or two torps if possible. And when I'm in position a few Emeralds/Rubies fly to these small webs (four or five are enough). With that tactics I was able to lay 5 overlapping webs over a carrier fleet that was around 100ly away. They had to recycle their carriers but I still got two of them.
The Ruby is of course something you should build if you can't afford the Emerald. Not much difference...
The Emerald is the best medium ship in the game if you ask me. That fuel tank and cargo hold is tremendous! With just one Emerald (usually the Rubies and Emeralds should have mk7 or if money is no problem mk8 torps) you can lay almost two maximum webs... with mk8 torps you can lay two max webs!
The only problem you have as crystal is when your enemy comes with 5 or more ships with 10 beams each and all of them are heavy phasers or heavy disruptors. Then you have to fight. Laying webs is more or less impossible and a waste of ressources (but there is still a little hint... more later).
For that case I always have Diamonds and Thunders around... I build them in a 3/2 ratio. That combination is powerful and not too expensive. I think that is a fair deal for the tactical advantage you get from the webs. And the good thing is that every intercepting fleet can still hit a mine and if you have just 3 Diamonds and 2 Thunders for defense but your enemy has... let's say 5 Virgos you can still hope that only two or three will make it to your planet/base. Webs give you time to defend!!!
About that little hint.
Always funny to see my enemy at the edge of a web. I know he brought his best sweeper (of course that ship is what I want to destroy first if possible). In that case the opal can be extremely powerful again. You only need a ship with a lower ID than the sweeping ship. All you have to do is to fill up your ship with supplies or minerals... you need just 1 - 5kt cargo space open. Then you set the mission to sweep mines and the friendly code to "msc" and your ship scoops a few mines before the big sweeper starts to waste your minerals. The nice thing is that that can be enough (echoview helps). If your enemy is just 1ly within your web just a few torps must be scooped and he is 1 - 3ly outside of the web!!! Of course your naive enemy thinks he will sweep the web and set a waypoint for your planet or the next sweeping point. In that case he will hit a mine... pretty sure.
If your enemy is not so stupid he has just two options.
ignore the webs and accept any minehit he will get (good for you in any way) or it will take ages to advance just around 5ly per turn... and still have the chance to pass around 1 - 3ly through your web and hit a mine every turn. No matter what happens... your enemy will lose fuel and you have some more time to bring your big ships (if you have them)
...sometimes I ask myself why I post my most beloved tactics...
Yes... and never forget to be well prepared. Nothing worse than a web that was just not big enough. If you know the enemy ship has 10 heavy phasers and you lay a 3000 mines web just let it be. Then you have to retreat or fight. A good crystal can hit every enemy that is not prepared to sweep webs and the best crystal just has more webs than a normal fleet can sweep (and of course some combos for bigger fleets).
When I laid those 5 overlapping webs I had around 2500 torps ready for laying... and Rubies and Emeralds were bringin additional torps all the time. I knew that this fleet had not the best beams and my calculation told me that I could keep up those 5 webs for almost 10 turns. ...125kt fuel drain every turn even without moving really hurts
Of course my ally had the cloakers to tow away ships that just have 1kt and sweep mines. Otherwise it wouldn't work.
Well... Crystals are cool
Oderint dum metuant.
Bella gerant alii, tu, felix Austria, nube!