diff --git a/src/Purl/Fragment.php b/src/Purl/Fragment.php
index 96706b0..ccd9d11 100644
--- a/src/Purl/Fragment.php
+++ b/src/Purl/Fragment.php
@@ -7,6 +7,8 @@
 use function array_merge;
 use function parse_url;
 use function sprintf;
+use function strpos;
+use function substr;
 
 /**
  * Fragment represents the part of a Url after the hashmark (#).
@@ -109,8 +111,13 @@ public function __toString() : string
     protected function doInitialize() : void
     {
         if ($this->fragment !== null) {
+            $pos   = strpos($this->fragment, ':', 1);
+            $colon = '';
+            if ($pos !== false) {
+                $colon = substr($this->fragment, $pos);
+            }
             $data = parse_url($this->fragment);
-            if ($data === false) {
+            if ($colon !== '') {
                 $data = ['path' => $this->fragment];
             }
 
diff --git a/tests/Purl/Test/UrlTest.php b/tests/Purl/Test/UrlTest.php
index 23ee2d0..6fe671b 100644
--- a/tests/Purl/Test/UrlTest.php
+++ b/tests/Purl/Test/UrlTest.php
@@ -365,7 +365,7 @@ public function testRelativeUrl() : void
 
         // test fragment with colon
         $url = new Url('http://example.com/#hello:123');
-        $this->assertEquals('http://example.com/', (string) $url);
+        $this->assertEquals('http://example.com/#hello:123', (string) $url);
     }
 }