SQL Range Query For un-Order alphabet data value

DECLARE @tmp TABLE(Clarity VARCHAR(30), RowNo INT)

--get all Clarities 
;WITH Clarities AS
(
    SELECT 1 AS RowNo, Clarity
    FROM YourTable
    UNION ALL
    SELECT RowNo + 1 AS RowNo, Clarity
    FROM Clarities
)
INSERT INTO @tmp (Clarity, RowNo)
SELECT Clarity, RowNo
FROM Clarities
--uncomment below line if no. of Clarities in your table is more than 100
--OPTION (MAXRECURSION 0)

--declare variables to get first and last clarity no.
DECLARE @firstClarity INT
DECLARE @lastClarity INT

--get id for the first clarity
SELECT @firstClarity = MIN(RowNo)
FROM @tmp
WHERE Clarity = 'FL' 
--get id for the last clarity
SELECT @lastClarity = MAX(RowNo)
FROM @tmp
WHERE Clarity = 'VVS1' 

--result query:
SELECT t1.Clarity
FROM YourTable AS t1 LEFT JOIN @tmp AS t2 ON t1.Clarity = t2.Clarity
WHERE t2.RowNo BETWEEN @firstClarity AND @lastClarity