diff --git a/CREDITS b/CREDITS
index 66604eb..44e55a8 100644
--- a/CREDITS
+++ b/CREDITS
@@ -46,3 +46,7 @@ http://old.cescg.org/CESCG-2002/DSykoraJJelinek/
 
 7. Quaternions
 Initial mat4_quat is borrowed from Apple's simd library
+
+
+8. Vector Rotation using Quaternion
+https://gamedev.stackexchange.com/questions/28395/rotating-vector3-by-a-quaternion
diff --git a/include/cglm/quat.h b/include/cglm/quat.h
index effebae..664a069 100644
--- a/include/cglm/quat.h
+++ b/include/cglm/quat.h
@@ -168,7 +168,7 @@ glm_quat_normalize_to(versor q, versor dest) {
 
   x0   = _mm_load_ps(q);
   xdot = glm_simd_dot(x0, x0);
-  dot = _mm_cvtss_f32(xdot);
+  dot  = _mm_cvtss_f32(xdot);
 
   if (dot <= 0.0f) {
     glm_quat_identity(dest);
@@ -676,4 +676,32 @@ glm_quat_forp(vec3 from, vec3 to, vec3 fwd, vec3 up, versor dest) {
   glm_quat_for(dir, fwd, up, dest);
 }
 
+/*!
+ * @brief rotate existing transform matrix using quaternion
+ *
+ * @param[in]   q     quaternion
+ * @param[in]   v     vector to rotate
+ * @param[out]  dest  destination vector
+ */
+CGLM_INLINE
+void
+glm_quat_rotatev(versor q, vec3 v, vec3 dest) {
+  versor p;
+  vec3   u, v1, v2;
+  float  s;
+
+  glm_quat_normalize_to(q, p);
+  glm_quat_imag(p, u);
+  s = glm_quat_real(p);
+
+  glm_vec_scale(u, 2.0f * glm_vec_dot(u, v), v1);
+  glm_vec_scale(v, s * s - glm_vec_dot(u, u), v2);
+  glm_vec_add(v1, v2, v1);
+
+  glm_vec_cross(u, v, v2);
+  glm_vec_scale(v2, 2.0f * s, v2);
+
+  glm_vec_add(v1, v2, dest);
+}
+
 #endif /* cglm_quat_h */
diff --git a/test/src/test_common.c b/test/src/test_common.c
index bd6deaf..514c006 100644
--- a/test/src/test_common.c
+++ b/test/src/test_common.c
@@ -86,9 +86,9 @@ test_assert_mat4_eq2(mat4 m1, mat4 m2, float eps) {
 
 void
 test_assert_vec3_eq(vec3 v1, vec3 v2) {
-  assert_true(fabsf(v1[0] - v2[0]) <= 0.0000009); /* rounding errors */
-  assert_true(fabsf(v1[1] - v2[1]) <= 0.0000009);
-  assert_true(fabsf(v1[2] - v2[2]) <= 0.0000009);
+  assert_true(fabsf(v1[0] - v2[0]) <= 0.000009); /* rounding errors */
+  assert_true(fabsf(v1[1] - v2[1]) <= 0.000009);
+  assert_true(fabsf(v1[2] - v2[2]) <= 0.000009);
 }
 
 void
@@ -101,9 +101,9 @@ test_assert_quat_eq_abs(versor v1, versor v2) {
 
 void
 test_assert_quat_eq(versor v1, versor v2) {
-  assert_true(fabsf(v1[0] - v2[0]) <= 0.0000009); /* rounding errors */
-  assert_true(fabsf(v1[1] - v2[1]) <= 0.0000009);
-  assert_true(fabsf(v1[2] - v2[2]) <= 0.0000009);
-  assert_true(fabsf(v1[3] - v2[3]) <= 0.0000009);
+  assert_true(fabsf(v1[0] - v2[0]) <= 0.000009); /* rounding errors */
+  assert_true(fabsf(v1[1] - v2[1]) <= 0.000009);
+  assert_true(fabsf(v1[2] - v2[2]) <= 0.000009);
+  assert_true(fabsf(v1[3] - v2[3]) <= 0.000009);
 }
 
diff --git a/test/src/test_quat.c b/test/src/test_quat.c
index 1c1502d..43dbdb2 100644
--- a/test/src/test_quat.c
+++ b/test/src/test_quat.c
@@ -20,7 +20,7 @@ void
 test_quat(void **state) {
   mat4   inRot, outRot, view1, view2, rot1, rot2;
   versor inQuat, outQuat, q3, q4, q5;
-  vec3   eye, axis, imag;
+  vec3   eye, axis, imag, v1, v2;
   int    i;
 
   /* 0. test identiy quat */
@@ -134,7 +134,25 @@ test_quat(void **state) {
   imag[1] = -1.0f;
   imag[2] =  0.0f;
 
-  assert_true(glm_vec_eqv_eps(imag, axis));
+  test_assert_vec3_eq(imag, axis);
+
+  /* 10. test rotate vector using quat */
+  /* (0,0,-1) around (1,0,0) must give (0,1,0) */
+  v1[0] = 0.0f; v1[1] = 0.0f; v1[2] = -1.0f;
+  v2[0] = 0.0f; v2[1] = 0.0f; v2[2] = -1.0f;
+
+  glm_vec_rotate(v1, glm_rad(90.0f), (vec3){1.0f, 0.0f, 0.0f});
+  glm_quatv(q3, glm_rad(90.0f), (vec3){1.0f, 0.0f, 0.0f});
+
+  glm_vec4_scale(q3, 1.5, q3);
+  glm_quat_rotatev(q3, v2, v2);
+
+  /* result must be : (0,1,0) */
+  assert_true(fabsf(v1[0]) <= 0.00009f
+              && fabsf(v1[1] - 1.0f) <= 0.00009f
+              && fabsf(v1[2]) <= 0.00009f);
+
+  test_assert_vec3_eq(v1, v2);
 
   /* TODO: add tests for slerp, lerp */
 }