Shall I use “virtual” keyword for destructor of base-class which is actually an interface?

type TInterfaceMethod = class
  public
    destructor Destroy; virtual; abstract;
    procedure Calculate; virtual; abstract;
    procedure PrepareForWork; virtual; abstract;
end;
type ConcreteMethod = class(TInterfaceMethod)
  private
    matrix: TMinMatrix;
  public
    constructor Create(var matr: TMinMatrix);
    procedure Calculate; override;
    procedure PrepareForWork; override;
    destructor Destroy;
end;

type
  TInterfaceMethod = class abstract
  public
    destructor Destroy; override; abstract;
    procedure Calculate; virtual; abstract;
    procedure PrepareForWork; virtual; abstract;
  end;

  TConcreteMethod = class(TInterfaceMethod)
  private
    matrix: TMinMatrix;
  public
    constructor Create(var matr: TMinMatrix);
    procedure Calculate; override;
    procedure PrepareForWork; override;
    destructor Destroy; override;
  end;