The gotcha is that the types of Marble you can attune to is limited by your perception. For the more exotic types of Marble, you'll need a boost from eating Perception Food.
Zigzag Area Search for either of TWO Marbles
Our recommendation is that you and your partner attune to DIFFERENT types of Marble so that you can search for two types of Marble at once.When you select ESC > Special > Prospect for <your Marble>, you'll get one of three results.
- Two Slate Break means that <your Marble> is somewhere in the search circle. The line between you and your partner is a DIAMETER of that search circle.
- One Slate Break means that you searched properly, but there's no Marble.
- Zero Slate Break means that you and your partner are too far apart to Prospect for Marble.
The largest possible search DIAMETER is a relative (0,0) to (31,31) which is 45.25 coordinates. It's much easier if you simply use 30 coordinates of separation, a relative (0,0) to (30,30), and you can go faster as the search will still work just fine if you're not quite precisely on target. If you stagger alternate sweeps, the search circles will fit nicely together. The recommended offset is X + 35 and Y+15. The precise X value would be X = 31*((1+sqrt(2)))/2 = 37.4, so offsetting by only 35 coordinates leaves you with a couple coordinates of overlap for fighting with the terrain.
Follow the recommended 60 coordinate zigzag pattern until you find a "Two Slate Break".
You and your partner should be attuned to DIFFERENT Marbles. You and your Partner should aternately move 60 coordinates but you should BOTH Prospect for Marble after EACH move.
If there already a Quarry of your type in the area, simply ensure that your partner is between you and the existing Quarry, and you'll never see it.
Note that you're "wasting" one coordinate because you're only searching a diameter of 31 rather than 32. The advantage is that you can move with minimal coordination, and can efficiently cover a lot of territory. By staggering passes, you can fill in the spaces between the circle, covering the gaps rather than doing a redundant check.
Double F8 (north facing cartography) is the best view. Use /clockloc and drag it right next to your avatar.
The kind of terrain (except water) doesn't matter for the Marble, but prospecting in mountainous terrain can be a pain.
When either of you get a "Two Slate Break", go the next section and isolate the related Quarry.
Move Halfway Toward Me
Now that you have found a "Two Slate Break" in a very large circle, one with a diameter as large as (0,0) to (31,31) or 32*sqrt(2)=45.25 coordinates, you need to efficiently determine where to build your Quarry.You'll do most of the running around and all of the Prospecting for <your Marble>. The isolation pattern begins by moving your partner halfway towards you. This establishes the rotated SIDE of the next inscribed quartering square. If you enter your partner's coordinates into the map, the program will adjust all of the numbers so that you can easily follow the action. You can print out the map if you wish, but printed Excel graphics aren't particularly accurate. After your partner moves, before you break any more slate, you'll make a move that's tricky and counter-intuitive. You will move at 90 degrees to your partner's direction of travel, and half again further (sqrt(2)). Your partner is moving to the center of the new smaller search square, but you're moving to the rotated corner of the search square.
The key concept is that a "Two Slate Break" always reduces the size of the search circle. You can therefore isolate your Quarry by prospecting closer and closer to the actual center. We've only shown the successful "Two Slate Breaks". The unsuccessful "One Slate Breaks" were the the same distance from the Partner, but in the wrong direction.
Each "Two Slate Break" circle is quartered by using smaller circles that include the center of the "Two Slate Break" circle and the two corners of an inscribed square. The area of the search circle (and the inscribed square) reduces by half with each iteration. The circle that's used to "quarter" the larger circle actually covers 34% of the larger circle.
When you find a Two Slate Break where the locations for you and your partner differ by only one coordinate, in one direction (NSEW), move your partner to the midpoint between the intersections. That's the location of your Marble.
For this snapshot, we found the exact intersections for the local cells by finding the spot where a single diagonal step took us from (0,0) to (1,1), and we then dropped a tadpole at the (1,1) point.
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From a Geometry point of view, what we're actually doing is rotating an inscribed square by 45 degrees for each iteration, and always searching a diagonal.
For those of you who are fond of Geometry, assuming a radius of 1 for the larger circle,
- the Area of the larger circle is Pi * r^2 = Pi *1 = Pi.
- the Area of the inscribed square is sqrt(2) * sqrt(2) = 2.
- the Area of the quartering circle is Pi * 1/sqrt(2)^2 = Pi/2, one half the size of the larger circle.
- the Area of the square inscribed in the quartering circle is r*r = 1.
- the Area that is common to both circles is therefore (Pi/2 - 1) + Pi/4 = 1.07
- the Area tested by the quartering circle is therefore ((Pi/2 - 1) +Pi/4)/Pi = 34.08%, not 25%.
- If you test first one side and then the opposite side, the first two tests cover 68% of the area.
Your "Slate Break" moves are actually very simple, once your partner has moved.
- 31 Diagonal (this was our Zigzag search) - both coordinates differed by 32 (or perhaps a bit less)
- 31 Cardinal (North South East West) - one coordinate differs by 31
(we'll fudge just a bit, so your partner won't have to move) - 16 Diagonal - both coordinates differ by 16
- 16 Cardinal - one coordinate differs by 16
- 8 Diagonal - both coordinates differ by 8
- 8 Cardinal - one coordinate differs by 8
- 4 Diagonal - both coordinates differ by 4
- 4 Cardinal - one coordinate differs by 4
- 2 Diagonal - both coordinates differ by 2
- 2 Cardinal - one coordinate differs by 2
- 1 Diagonal - both coordinates differ by 1
- 1 Cardinal - one coordinate differs by 1
- 0.5 Midpoint - Build your Quarry.
How much Slate will I need to find a Quarry?
If you are using the recommended 60 coordinate zigzag, the search pattern will look like a very tall snowman.- The area of each search circle is Pi*(30*sqrt(2)/2)^2 = 1414 cells.
- The area of the inscribed square is 30*30 = 900 cells, so you get a bonus of 514 cells..
Isolating the Quarry is more difficult. We'll need 11 iterations to get from 1414 cells to 1 Quarry. Because of the area covered by the quartering circles, 100 quartering trials would need
- 2 Slate 34 times
- 3 Slate 34 times
- 4 Slate 16 times
- 5 Slate 16 times
On average, finding a Quarry using the recommended procedures will therefore take 4 Slate to find a Two Slate Break, plus 34.5 more Slate to isolate the Quarry.
We've ignored the fact that you are BOTH prospecting. That's just quicker, not more efficient. If you are averaging less than 38.5 Slate per Quarry, let's talk.
Here's the search data for an OSM Quarry that was built Year 3, Akhet III-5 using 36 Slate. The previous Oyster Shell Marble Quarry was built the day before at 1301 2424. We were prospecting from south to north, so read the data from the bottom up.
| Move | X = | Y = | Result |
| BUILD | 1292 | 2476 | QUARRY |
| verify 1C | 1293 | 2476 | TWO |
| verify 1C | 1291 | 2476 | TWO |
| verify 1C | 1292 | 2475 | TWO |
| verify 1C | 1292 | 2477 | TWO |
| NONE | 1292 | 2476 | |
| 1D | 1293 | 2477 | TWO |
| HALF | 1292 | 2476 | |
| 2C | 1292 | 2477 | TWO |
| HALF | 1292 | 2475 | |
| 2D | 1293 | 2476 | TWO |
| 2D | 1289 | 2472 | ONE |
| 2D | 1289 | 2476 | ONE |
| 2D | 1293 | 2472 | ONE |
| HALF | 1291 | 2474 | |
| 4C | 1291 | 2472 | TWO |
| HALF | 1291 | 2476 | |
| 4D | 1289 | 2474 | TWO |
| HALF | 1293 | 2478 | verify |
| 8C | 1289 | 2478 | TWO |
| 8C | 1297 | 2486 | ONE |
| 8C | 1297 | 2470 | ONE |
| HALF | 1297 | 2478 | |
| 8D | 1301 | 2474 | TWO |
| HALF | 1293 | 2481 | |
| 16C | 1293 | 2473 | TWO |
| 16C | 1293 | 2505 | ONE |
| HALF | 1293 | 2489 | |
| 16D | 1301 | 2497 | TWO |
| HALF | 1285 | 2481 | |
| 32C | 1285 | 2497 | TWO |
| HALF | 1285 | 2465 | |
| ZIGZAG | 1270 | 2480 | TWO |
| PARTNER | 1300 | 2450 |
We've entered the Quarry coordinates on the map, so you can also follow the action graphically.
The initial Two Slate Break was outside of the search square, nearly to the edge of the search circle. The important concept for following the action is that each midpoint (Half point) is quaranteed to be somewhere in a smaller search circle. We then quarter that circle so we can make the next search circle even smaller. We're cutting the possible quarry locations in half each time we get a successful "Two Slate Break".
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Building a Stone_Quarry
Construction costs:Built: outside (projects menu)
Skill/Tech required: Rock of the Ages
Prospecting Tools
If you have access to Microsoft Excel, you can download the attached Prospecting.xls spreadsheet and set the coodinates for your own searches.
