Crystal Mine

Crystal is the middle resource in SFC2. It sits between ore and hydrogen in both value and how fast you get it. Almost everything wants crystal: ships, defenses, buildings and every level of research. It comes out of the ground slower than ore, and being short of crystal is the normal state of affairs for most of the early game.

The Crystal Mine is where it comes from. Every planet has one, and you raise its level on the Buildings page. New planets start it at level 0. Moons have no mines at all, and a deployed Hephaestus platform does not mine either.

What it produces

Crystal per hour = (20 × Level × 1.1^Level, rounded down) × 2, plus a flat 20 per hour.

That flat 20 is the trickle every planet gets for free. A brand new planet with the mine still at level 0 makes 20 crystal an hour and 40 ore an hour, which is what gets you started.

Above level 30 the exponent stops climbing at the normal rate. Instead of 1.1^Level the game uses 1.1^{30 + ln(Level - 29)}, so production almost flattens out. Energy use does not get that treatment, it keeps doubling up the same curve it always did. Levels past 30 cost a fortune, add very little crystal and burn a lot more power. Very few players go there on purpose.

Energy

Mines only run flat out if the planet makes at least as much energy as its mines want. If you are short, every mine on the planet runs at produced divided by needed. A planet that produces 4,563 energy but needs 6,244 is running at 73%, so a level 21 Crystal Mine that should do 6,236 crystal an hour only manages about 4,560.

The Buildings page tells you this in two places. Each mine shows "Production: x of y/hr" with an "Insufficient Energy" warning under it, and the Energy panel in the sidebar shows used against produced. Energy comes from the Solar Array, the Nuclear Power Plant and solar satellites.

The free 20 per hour is the one part that ignores energy. Even with zero power on the planet you still get it.

Crystal_production_panels_sfc2.jpg 83.7 KB

The capacity setting

Every mine has a Capacity dropdown that runs from 0% to 100% in steps of 5. Turning a mine down cuts its output and its energy draw by the same percentage. A level 17 Crystal Mine at 100% makes 3,456 crystal an hour and eats 860 energy. Drop it to 50% and it makes 1,738 an hour and eats 430.

It is worth knowing about when you are power starved and would rather put what energy you have into the Ore Mine, or when you want to stop a mine filling a store you are about to need for something else. Set it to 0% and the mine stops, except for the free 20 per hour, which still comes in.

Storage

A planet holds 100,000 crystal to start with. The Crystal Warehouse raises that:

Capacity = 100,000 + 50,000 × (1.6^{Warehouse level} rounded up - 1)

Warehouse level	Crystal capacity
0	100,000
1	150,000
2	200,000
3	300,000
4	400,000
5	600,000
6	900,000
7	1,400,000
8	2,200,000
9	3,500,000
10	5,550,000

When the store fills up the mine stops. Not slows down, stops. The crystal figure in the top right of the interface turns red when you are at or over the cap, and the Storage panel on the Buildings page puts a "Capacity Exceeded" warning on itself. To get going again, spend the crystal, move it off the planet with a transport or a resource save, or build another warehouse level.

Plunder, mission rewards and trades can all push you past the cap. Nothing is lost when that happens, the mine just sits idle until you are back under.

Mines run all the time, not in hourly lumps. The counter in the top right refreshes about once a minute while you have the game open, and again on every page load.

Building it up

The cost of a level does not depend on the planet:

Ore = 48 × 1.6^{Level - 1}, rounded down
Crystal = 24 × 1.6^{Level - 1}, rounded down

Build time does depend on the planet:

Hours = (Ore + Crystal) ÷ (5,000 × (Capitol level + 1) × 2^{Foundry level})

So a Capitol level and a Foundry level both pay for themselves across every mine you will ever build. A Foundry level halves the time on its own.

Two other things to keep in mind. Each mine level uses one field, so a level 25 Crystal Mine is 25 fields of a planet that might only have 150. And a planet can only build one thing at a time, so a long mine upgrade blocks everything else on that planet until it finishes.

The More Info button on the mine gives you the next few levels, what they produce, what they cost and what they will do to your energy.

Tearing a level back down

You can tear down a mine level. It costs one third of what that level cost to build and takes one third of the build time, and you pay it, there is no refund. What you get back is the field and the energy draw. It is a repair for a planet you overbuilt, not a way to move resources around.

Other ways to get crystal

Mining is not the only source, and past the early game it is usually not the biggest one.

Attacking players and NPC encounters. You take a share of what is sitting on the target, see Plunder.
Debris. Destroyed ships leave 30% of their build cost floating in orbit as ore and crystal, and recyclers bring it home. Big battles put a lot of crystal on the board.
Missions, secret missions, quests and the Lucky Draw.
The Trade Merchant, which converts one resource into another for 5,000 credits a go. The rate is 1.5 ore to 1 crystal, and 1 crystal to 0.6 hydrogen. See Trading.

What slows production down

Not enough energy. Covered above. This is the common one.
Full storage. Production stops dead at the cap.
Diplomacy Mode. Buys you protection from attack and charges you production for it. The cut is 25% under 50k RSP, 50% from 50k to 99,999 RSP, and 75% at 100k RSP and up. It applies to the free 20 per hour as well.
Vacation Mode. Production stops completely while you are parked.
The capacity setting, if you have turned the mine down and forgotten about it.

Cost, energy and production by level

Ore and crystal are what that level costs to build. Energy is what the mine draws once it is at that level. Crystal per hour is the full rate at 100% energy and 100% capacity, including the free 20. Gain is the extra you get over the level below. Hours to pay off takes the whole bill, converts the ore half to crystal at the Merchant's 1.5 to 1 rate, and divides by the gain, so it is roughly how long the upgrade takes to earn itself back.

Level	Ore cost	Crystal cost	Energy use	Crystal per hour	Gain	Hours to pay off
0	-	-	0	20	-	-
1	48	24	11	64	+44	1.3
2	76	38	25	116	+52	1.7
3	122	61	40	178	+62	2.3
4	196	98	59	254	+76	3.0
5	314	157	81	342	+88	4.2
6	503	251	107	444	+102	5.7
7	805	402	137	564	+120	7.8
8	1,288	644	172	704	+140	11
9	2,061	1,030	213	868	+164	15
10	3,298	1,649	260	1,056	+188	20
11	5,277	2,638	314	1,274	+218	28
12	8,444	4,222	377	1,526	+252	39
13	13,510	6,755	449	1,814	+288	55
14	21,617	10,808	532	2,146	+332	76
15	34,587	17,293	627	2,526	+380	106
16	55,340	27,670	736	2,960	+434	149
17	88,544	44,272	860	3,456	+496	208
18	141,670	70,835	1,001	4,022	+566	292
19	226,673	113,336	1,163	4,668	+646	409
20	362,677	181,338	1,346	5,400	+732	578
21	580,284	290,142	1,555	6,236	+836	810
22	928,455	464,227	1,791	7,182	+946	1,145
23	1,485,528	742,764	2,060	8,256	+1,074	1,614
24	2,376,844	1,188,422	2,364	9,474	+1,218	2,277
25	3,802,951	1,901,475	2,709	10,854	+1,380	3,215
26	6,084,722	3,042,361	3,099	12,414	+1,560	4,551
27	9,735,556	4,867,778	3,540	14,178	+1,764	6,439
28	15,576,890	7,788,445	4,038	16,170	+1,992	9,123
29	24,923,024	12,461,512	4,601	18,420	+2,250	12,923
30	39,876,839	19,938,419	5,235	20,958	+2,538	18,331
31	63,802,943	31,901,471	5,951	23,134	+2,176	34,208
32	102,084,710	51,042,355	6,757	24,820	+1,686	70,640
33	163,335,536	81,667,768	7,665	26,306	+1,486	128,236
34	261,336,857	130,668,428	8,687	27,684	+1,378	221,258
35	418,138,972	209,069,486	9,836	28,998	+1,314	371,255
36	669,022,355	334,511,177	11,129	30,266	+1,268	615,557
37	1,070,435,769	535,217,884	12,582	31,504	+1,238	1,008,757
38	1,712,697,231	856,348,615	14,214	32,720	+1,216	1,643,213
39	2,740,315,569	1,370,157,784	16,047	33,920	+1,200	2,664,196
40	4,384,504,911	2,192,252,455	18,104	35,106	+1,186	4,313,032

Look at what happens either side of level 30. Level 25 costs 3.8 million ore and 1.9 million crystal and buys you 1,380 more crystal an hour. Level 35 costs 418 million ore and 209 million crystal and buys you 1,314 an hour, which is less, while adding another 1,149 to your energy bill. The curve turns over, and it turns over hard.

For most players the sensible answer is to keep the Crystal Mine a couple of levels behind the Ore Mine, keep both fed with power, and spend the difference on ships. See Mines for how the three mines compare.