PEARLS, RUBIES, GARNETS, EMERALDS, ETC.

For quick reference, definitions of above terms :

PEARL :

A Pearl is a minimal sudoku where the first solvable cell is difficult to solve. The more difficult, the greater the pearl and its value.

A small pearl would require more than elementary technique, i.e. more than singles, pairs, trips, quads and locked candidates.

A large pearl would require more than SSTS, ie more than elementary technique plus Swordfish, X-Wing, XY-Wing, 2-colour and 4-colour chains.

If the puzzle is not minimal, i.e. contains any redundant clue/s, then the pearl is a fake, by definition. This definition is necessary to protect the scarcity value of pearls, otherwise any non-pearl could be made into a pearl by inserting additional clues until a point of difficulty was reached.

Two great examples of pearls : Ocean's Pearl Brooch and Claudia's Star of Arabia.

RUBY :

A Ruby is, strictly speaking, a non-conjugate candidate x in a sudoku, whose removal from a cell at the very start of the solution leads to a contradiction and whose placement leads to solution, both processes requiring no more techniques than SSTS, and preferably even a simpler set of techniques.

The simpler the techniques required, the greater the Ruby.

Non-conjugacy requires that there be more than 2 candidates in the Ruby Cell, and that the Ruby not be a member of a conjugate pair of x in row, column or box.

The greater the non-conjugacy, i.e. the more candidates in the Ruby cell, and the more other x-candidates in the row, column and box, the greater the Ruby.

The non-conjugacy rule increases the scarcity value of rubies, and so makes them deserving jewels.

Finally, the greater the overall difficulty of the puzzle, the greater the Ruby. A Ruby requires a puzzle that requires more than elementary techniques to solve. Note that the Ruby CONTAINS only simple techniques, but is not ITSELF a simple technique but the start of a Forcing Net or other more complex technique.

GARNET :

A Garnet is the same as a Ruby, except that it is not present at the very start of the solution, but arises later. Garnets are of less value than rubies, because they occur far more frequently.

EMERALD :

An Emerald is defined as a sudoku with clues which are symmetrical in their natures and mutual relationships as well as in their positions.

A prime example of an Emerald is Tso's Puzzle, made famous by Carcul in his controversial "Riddle of Sho".

TURQUOISE:

A Turquoise is defined as a minimal sudoku where it is difficult to eliminate the first candidate. It can be measured as the SE rating of the first step, required to eliminate the first candidate.

JADE:

Somewhat loosely defined as a sudoku which starts off easy and becomes hard later. The ultimate Jade would be the puzzle starting with the most singles, followed by an extreme jump in SE rating for the next step.

re: Precious Stones Guidebook

Tarek,

I have opened THIS topic "PEARLS, RUBIES, GARNETS, EMERALDS, ETC." giving definitions of these terms, for which I am responsible.

DIAMONDS are not my province, but rather udosuk's I think. Refer to him regarding diamonds, please.

udosuk,

and anyone else, please feel free to use the new topic to add your own jewelry definitions. Then everything will stay together for ready reference.

For that matter, why confine yourself to gemstones? Anything goes! Maybe flowers... Or else proper names such as "Mona Lisa" ?