Just as a cut diamond's facets can change a light ray's plane of travel, the word 'diamond' in a cryptic clue can take many forms to send the solver off on a wrong course.
Some popular ways in which setters craft clues with 'diamond' in them:
A Suit Of Cards
Diamond is one of the four playing card symbols. Cryptic clues typically use diamond as the gemstone on the clue's surface and a playing card in the answer.
Guardian 25320 (Brendan): Bachelor with one diamond, say, for movie actress (6) BACALL
BA (bachelor) CALL ('one diamond', an example of a call in a card game)
Times 24860: Criticising valuable diamond, perhaps, after turning up nose (8) KNOCKING
KING (a high-value diamond in a card game), after CONK (nose) reversed
The 60th Anniversary
The 60th anniversary of an event such as a wedding, or the length of time a monarch has reigned, is a diamond jubilee.
Times 4425: An anniversary for which there could be an 'icy' reception? (7,7) DIAMOND WEDDING dd
Times 24506: Did adding women upset big union anniversary? (7,7) DIAMOND WEDDING
(DID ADDING WOMEN)*
The abbreviation for 'diamonds' in playing cards. Useful to setters for adding/deleting a letter in the answer.
Guardian 25292 (Bonxie): Old hat with diamonds? Nothing better! (5) OUTDO
OUT (old hat) D (diamonds) O (nothing)
FT 13377 (Aardvark): Writer’s agent wearing diamonds similarly (2,4) IN KIND
INK (writer's agent) IN (wearing) D (diamonds)
Slang for diamond(s).
FT 13695 (Phssthpok): Prominent celebrity wears diamonds (10) NOTICEABLE
NOTABLE (celebrity) around ICE (diamonds)
Times 24999: Several times getting tips from tutor holding hearts and diamonds (6) THRICE
T[uto]R around H, ICE (diamonds)
Another slang for diamond.
FT 13093 (Monk): Fake diamond's a national emblem (8) SHAMROCK
SHAM (fake) ROCK (diamond). The national symbol of Ireland.
Guardian 24309 (Brendan): Pass a diamond to Nick in play and finish in lowest position (5,4,6) REACH ROCK BOTTOM
REACH (pass) ROCK (diamond) BOTTOM (Nick in play - character in Shakespeare's AMND)
The baseball field
The field on which baseball is played is called a 'diamond'.
Jumbo 881: Components of ring perhaps where some Americans find sporting action (8) DIAMONDS dd
Guardian 25239 (Rufus): He plays in clubs and diamonds (8,6) BASEBALL PLAYER cd
A baseball player plays for a sporting club, in a baseball diamond.
The Shape ◊
The rhombus shape, called a 'diamond' after the diamond suit in playing cards.
THC (Buzzer): Wild mob rush for a diamond (7) RHOMBUS
Times 23499: Like diamonds, for example, all are quite different (11) EQUILATERAL
(ALL ARE QUITE)*. In a rhombus, all sides are of equal length.
FT 13161 (Alberich): Ginger Spice gives diamond maybe to a relative in the States (8) C_______
Times 24059: One beset by goddamned wind spoiled celebration for pensioners (7,7)
Guardian 25387 (Paul): Building provided rocks behind shed, half removed (7) E______
Everyman 3373: Replace wonderful watch studded with diamonds (9) S_______
If you wish to keep track of further articles on Crossword Unclued, you can subscribe to it in a reader via RSS Feed. You can also subscribe by email and have articles delivered to your inbox, or follow me on twitter to get notified of new links.